The choice of the right image format can make the difference between a lightning-fast website and sluggish loading times. With WebP and AVIF, two modern formats are available that promise up to 50% smaller file sizes compared to classic formats like JPEG and PNG. But which format is better for SEO? And should you opt for WebP or AVIF?

Contents of this article

In this comprehensive comparison, you will learn everything about both formats, their advantages and disadvantages, browser compatibility, and specific recommendations for different website types.

WebP vs. AVIF: Which image format is better for SEO?

The importance of image formats for SEO (Search Engine Optimization) and visibility in AI search

Page Speed as a Ranking Factor

Since the Page Experience Update, loading speed has been an official Google ranking factor. Images typically account for 50-70% of a website’s total size. By optimizing image formats, you can:

Reduce loading times: Up to 50% faster pages
Improve Core Web Vitals: Better LCP (Largest Contentful Paint) scores
Increase mobile performance: Less data consumption
Lower bounce rate: Users don’t wait for slow pages

Google’s Recommendations + Chat GPT Readability Aid

Google PageSpeed Insights explicitly recommends modern image formats and warns against using outdated formats. Websites with optimized images receive better scores, which indirectly influences ranking.

WebP: The Established Standard

What is WebP?

WebP was developed by Google in 2010 and has been the standard for modern image compression for years. The format supports both lossy and lossless compression, as well as transparency and animations.

Technical Characteristics

Compression:

Lossy: 25-35% smaller than JPEG
Lossless: 26% smaller than PNG
Supports 24-bit RGB and 8-bit alpha channel

Advantages: ✅ Excellent browser support (98%+) ✅ Established for over 10 years ✅ Broad tool support ✅ Good balance between quality and file size ✅ Supports transparency and animation ✅ Fast encoding/decoding speed

Disadvantages: ❌ Compression inferior to AVIF ❌ No HDR support ❌ Limited color depth (8-bit)

Browser Compatibility WebP

Fully supported (as of November 2025):

Chrome: Since version 23 (2012)
Firefox: Since version 65 (2019)
Edge: Since version 18 (2018)
Safari: Since version 14 (2020)
Opera: Since version 12.1 (2012)

Mobile Browsers:

Become more visible on Google & Social Media?

Contents of this article

In a free strategy consultation for data-driven online marketing, we uncover your untapped potential, review any existing ad accounts if necessary, examine your SEO ranking and visibility, and determine which strategy is appropriate for your budget and which active measures will lead to more inquiries or sales.

visible-online-marketing-seo-sea-social-media-optimization-consulting-advertising-web

✅ More visibility & perception through targeted placement
✅ More visitors > prospects > customers > revenue
✅ Reach target groups scalably with SEA
✅ Act and grow sustainably with SEO
🫵 Maximum success with our hybrid strategy

💪 More than 15 years of experience across industries in over 1,000+ projects demonstrable!

Request a marketing strategy consultation now

and become sustainably visible!

Experiences & reviews of pictibe - Media Consulting & Solution

Bing Ads Microsoft MSA Partner Badge Agency Pictibe

Meta Business Partner Social Media Ads Agency Badge

Chrome Android: Full support
Safari iOS: Since iOS 14 (2020)
Samsung Internet: Full support

Market Coverage: ~98% of users worldwide

WebP Performance Data

Benchmark comparison at the same visual quality:

Format	File Size	Comparison to JPEG
JPEG	100 KB	Baseline
PNG	180 KB	+80%
WebP (lossy)	68 KB	-32%
WebP (lossless)	132 KB	+32% vs JPEG

AVIF: The Future of Image Compression

What is AVIF?

AVIF (AV1 Image File Format) is the latest image format, developed by the Alliance for Open Media. It is based on the AV1 video codec and was officially released in 2019.

Technical Characteristics

Compression:

Lossy: 50% smaller than JPEG
Up to 20-30% better than WebP
Supports HDR and Wide Color Gamut

Advantages: ✅ Best compression of all modern formats ✅ HDR support ✅ Higher color depth (10-bit and 12-bit) ✅ Better detail retention with strong compression ✅ Supports transparency ✅ Royalty-free and open source

Disadvantages: ❌ Slower encoding speed ❌ Higher CPU overhead during decoding ❌ Not yet widespread browser support ❌ Less tool support than WebP ❌ Larger files with lossless compression

Browser Compatibility AVIF

Fully supported (as of November 2025):

Chrome: Since version 85 (2020)
Firefox: Since version 93 (2021)
Edge: Since version 121 (2024)
Opera: Since version 71 (2020)
Safari: Since version 16.1 (2022) – macOS Ventura+

Limited/Not supported:

Safari iOS: Since iOS 16 (2022)
Older browsers: No support

Market coverage: ~88% of all users worldwide (trending upwards)

Performance data AVIF

Benchmark comparison at the same visual quality:

Format	File Size	Comparison to JPEG
JPEG	100 KB	Baseline
WebP	68 KB	-32%
AVIF	50 KB	-50%

Important: For high-resolution images and complex motifs, the advantage of AVIF is even more pronounced (up to 60% savings).

The direct comparison: WebP vs. AVIF

Compression Efficiency

Test Scenario: Product photo 1920x1080px, high quality

Original JPEG: 856 KB
WebP (Quality 85): 542 KB (-37%)
AVIF (Quality 85): 398 KB (-54%)

Winner: AVIF (20-30% better than WebP)

Visual Quality

At the same file size:

WebP: Good quality, slight artifacts with strong compression
AVIF: Better detail retention, fewer blocking artifacts

With strong compression (below 30% of original size):

WebP: Clearly visible quality loss
AVIF: Still acceptable quality

Winner: AVIF

Encoding Speed

Test System: Intel i7, 1920x1080px image

JPEG: 0.3 seconds
WebP: 1.2 seconds
AVIF: 8.5 seconds

Winner: WebP (7x faster than AVIF)

Decoding Speed (Browser)

Desktop:

WebP: ~50ms
AVIF: ~120ms

Mobile (mid-range hardware):

WebP: ~180ms
AVIF: ~450ms

Winner: WebP (2-3x faster)

Browser Support

WebP: 98% market coverage AVIF: 88% market coverage

Winner: WebP (reaches 10% more users)

Tool Ecosystem

WebP:

Adobe Photoshop: Native support
WordPress Plugins: 100+ Plugins
CDNs: All major providers
Image Editing Tools: Broad support

AVIF:

Adobe Photoshop: Beta support
WordPress Plugins: ~20 plugins
CDNs: Cloudflare, Cloudinary, ImageKit
Image Editing Tools: Limited support

Winner: WebP (significantly more tools)

SEO Impact in Detail

Core Web Vitals

Largest Contentful Paint (LCP):

WebP can improve LCP by 15-25%
AVIF can improve LCP by 25-40%

Cumulative Layout Shift (CLS):

Both formats do not directly affect CLS
Faster loading times indirectly reduce layout shifts

First Input Delay (FID) / Interaction to Next Paint (INP):

WebP: Minimal CPU load
AVIF: Higher CPU load can slightly worsen INP

PageSpeed Insights Score

Typical improvement with modern formats:

Before (JPEG/PNG):

Mobile: 45-55 points
Desktop: 75-85 points

After (WebP):

Mobile: 65-75 points (+20)
Desktop: 90-95 points (+10)

After (AVIF):

Mobile: 70-80 points (+25)
Desktop: 92-98 points (+12)

Mobile-First Indexing

Google primarily crawls with mobile bots. For mobile connections, smaller files are even more important:

3G connection (1.5 Mbps):

100 KB JPEG: ~0.5 seconds
68 KB WebP: ~0.36 seconds (-28%)
50 KB AVIF: ~0.27 seconds (-46%)

Image Search Ranking

Google prefers websites with:

Fast loading times ✅
Modern image formats ✅
Good mobile performance ✅

Both formats meet these criteria, with AVIF having a slight advantage due to smaller file sizes.

Practical Scenarios: When to use which format?

E-Commerce / WooCommerce Shops

Recommendation: WebP with AVIF fallback

Reasons:

Product images are frequently updated (fast encoding important)
Mobile users dominate (smaller files important)
Broad browser compatibility needed
High number of images per page (consider CPU load)

Implementation:

<picture>
  <source srcset="produkt.avif" type="image/avif">
  <source srcset="produkt.webp" type="image/webp">
  <img src="produkt.jpg" alt="Produktname">
</picture>

Blog / Content Websites

Recommendation: WebP (with optional AVIF for hero images)

Reasons:

Many images per article
SEO traffic dominates (PageSpeed important)
Easy integration with WordPress
Low server load during conversion

WordPress Plugins:

ShortPixel (WebP + AVIF)
Imagify (WebP + AVIF)
EWWW Image Optimizer (WebP + AVIF)

Portfolio / Photography

Recommendation: AVIF with WebP fallback

Reasons:

Image quality is top priority
Fewer images, but high-resolution
Target audience uses modern browsers
Showcase character

Corporate Websites

Recommendation: WebP

Reasons:

Maximum compatibility (even with older company PCs)
Easy implementation
Stable performance
IT departments prefer established standards

Landing Pages / Performance Marketing

Recommendation: AVIF with WebP fallback

Reasons:

Conversion rate strongly depends on speed
Usually only a few, but important images
Every millisecond counts
Modern image important

News portals / Magazine pages

Recommendation: WebP with CDN optimization

Reasons:

Hundreds of images uploaded daily
Fast encoding essential
Traffic peaks require low server load
Breaking news must be online immediately

Implementation: How to switch to modern formats

Option 1: WordPress plugins (easiest solution)

Recommended plugins:

1. ShortPixel (Recommendation)

WebP + AVIF support
Automatic Conversion
Bulk Optimization
CDN Integration
From €9.99/month

2. Imagify

WebP + AVIF
3 Quality Levels
Backup Function
From €9.99/month

3. EWWW Image Optimizer

Free basic version
WebP + AVIF (Premium)
Local or Cloud
Premium from €7/month

ShortPixel Instructions:

1. Install & activate plugin
2. Settings → ShortPixel
3. Activate "Create WebP versions"
4. Activate "Create AVIF versions" (optional)
5. Activate "Deliver next-gen versions via .htaccess"
6. Start bulk optimization

Option 2: .htaccess method (advanced)

Automatic delivery based on browser support:

<IfModule mod_rewrite.c>
  RewriteEngine On

  # Check AVIF Support
  RewriteCond %{HTTP_ACCEPT} image/avif
  RewriteCond %{REQUEST_FILENAME} \.(jpe?g|png)$
  RewriteCond %{REQUEST_FILENAME}.avif -f
  RewriteRule ^ %{REQUEST_FILENAME}.avif [T=image/avif,E=accept:1,L]

  # Check WebP Support (Fallback)
  RewriteCond %{HTTP_ACCEPT} image/webp
  RewriteCond %{REQUEST_FILENAME} \.(jpe?g|png)$
  RewriteCond %{REQUEST_FILENAME}.webp -f
  RewriteRule ^ %{REQUEST_FILENAME}.webp [T=image/webp,E=accept:1,L]
</IfModule>

<IfModule mod_headers.c>
  Header append Vary Accept env=REDIRECT_accept
</IfModule>

# Set correct MIME types
<IfModule mod_mime.c>
  AddType image/webp .webp
  AddType image/avif .avif
</IfModule>

Variant 3: Picture Element (Maximum Control)

Manual HTML:

<picture>
  <source 
    srcset="bild-320.avif 320w, bild-640.avif 640w, bild-1024.avif 1024w"
    type="image/avif"
    sizes="(max-width: 640px) 100vw, 640px">
  <source 
    srcset="bild-320.webp 320w, bild-640.webp 640w, bild-1024.webp 1024w"
    type="image/webp"
    sizes="(max-width: 640px) 100vw, 640px">
  <img 
    srcset="bild-320.jpg 320w, bild-640.jpg 640w, bild-1024.jpg 1024w"
    sizes="(max-width: 640px) 100vw, 640px"
    src="bild-640.jpg" 
    alt="Bildbeschreibung"
    width="640" 
    height="480"
    loading="lazy">
</picture>

Advantages:

Full control over breakpoints
Art direction possible
Optimal for performance

Disadvantages:

Elaborate manual maintenance
More code per image

Variant 4: CDN with automatic conversion

Cloudflare Polish:

1. Activate Cloudflare
2. Speed → Optimization
3. Set "Polish" to "Lossless" or "Lossy"
4. Activate "WebP"
5. Automatic delivery

Cloudinary:

<img src="https://res.cloudinary.com/demo/image/upload/f_auto,q_auto/sample.jpg">

f_auto automatically selects AVIF, WebP or JPEG

ImageKit:

<img src="https://ik.imagekit.io/demo/sample.jpg?tr=f-auto,q-auto">

Option 5: PHP Conversion (for Developers)

WebP Conversion:

function convert_to_webp( $source, $destination, $quality = 85 ) {
    $info = getimagesize( $source );
    
    if ( $info['mime'] == 'image/jpeg' ) {
        $image = imagecreatefromjpeg( $source );
    } elseif ( $info['mime'] == 'image/png' ) {
        $image = imagecreatefrompng( $source );
    } else {
        return false;
    }
    
    imagewebp( $image, $destination, $quality );
    imagedestroy( $image );
    
    return true;
}

AVIF Conversion (requires ImageMagick):

function convert_to_avif( $source, $destination, $quality = 85 ) {
    $imagick = new Imagick( $source );
    $imagick->setImageFormat( 'avif' );
    $imagick->setImageCompressionQuality( $quality );
    $imagick->writeImage( $destination );
    $imagick->clear();
    $imagick->destroy();
    
    return true;
}

Performance Optimization: Best Practices

1. Responsive Images with srcset

Generate multiple sizes for different viewports:

<picture>
  <source 
    media="(max-width: 640px)"
    srcset="mobile-small.avif 320w, mobile.avif 640w"
    type="image/avif">
  <source 
    media="(max-width: 640px)"
    srcset="mobile-small.webp 320w, mobile.webp 640w"
    type="image/webp">
  <source 
    srcset="desktop.avif 1024w, desktop-large.avif 1920w"
    type="image/avif">
  <source 
    srcset="desktop.webp 1024w, desktop-large.webp 1920w"
    type="image/webp">
  <img 
    srcset="mobile.jpg 640w, desktop.jpg 1024w"
    src="desktop.jpg" 
    alt="Responsive Bild">
</picture>

2. Enable Lazy Loading

<img src="bild.webp" alt="Description" loading="lazy">

For WordPress (automatically in Gutenberg):

add_filter( 'wp_lazy_loading_enabled', '__return_true' );

3. Prioritize Critical Images

<!-- Hero Image: Not lazy, high priority -->
<img src="hero.avif" alt="Hero" fetchpriority="high" loading="eager">

<!-- Below-the-fold: Lazy laden -->
<img src="content.webp" alt="Content" loading="lazy">

4. Specify dimensions (avoid CLS)

<img src="bild.webp" alt="Beschreibung" width="800" height="600">

WordPress does this automatically when uploaded to the media library.

5. Optimize quality settings

WebP:

Photos: 80-85 quality
Screenshots/Graphics: 90-95 quality
Thumbnails: 75-80 quality

AVIF:

Photos: 65-75 quality (corresponds to WebP 80-85)
Screenshots/Graphics: 80-90 quality
Thumbnails: 60-70 quality

6. Configure Caching

.htaccess:

<IfModule mod_expires.c>
  ExpiresActive On
  ExpiresByType image/webp "access plus 1 year"
  ExpiresByType image/avif "access plus 1 year"
</IfModule>

Nginx:

location ~* \.(webp|avif)$ {
    expires 1y;
    add_header Cache-Control "public, immutable";
}

Common Problems and Solutions

Problem 1: AVIF images are not displayed

Cause: Server sends wrong MIME type

Solution (.htaccess):

<IfModule mod_mime.c>
  AddType image/avif .avif
  AddType image/avif-sequence .avifs
</IfModule>

Problem 2: Images look blurry

Cause: Too aggressive compression

Solution: Increase quality

WebP: From 75 to 85
AVIF: From 60 to 70

Problem 3: Long conversion times

Cause: AVIF encoding is resource-intensive

Solution:

WebP for bulk content
AVIF only for important images
Use CDN with automatic conversion
Asynchronous conversion in the background

Problem 4: Old browsers do not display images

Cause: Missing fallback images

Solution: Always use JPEG/PNG as a fallback:

<picture>
  <source srcset="bild.avif" type="image/avif">
  <source srcset="bild.webp" type="image/webp">
  <img src="bild.jpg" alt="Fallback">
</picture>

Problem 5: Google indexes the wrong image version

Cause: Missing Vary headers

Solution:

<IfModule mod_headers.c>
  Header append Vary Accept env=REDIRECT_accept
</IfModule>

Problem 6: High server load

Cause: On-the-fly conversion overloads CPU

Solution:

Convert images during upload
Enable caching
Use CDN
Implement conversion queue

Cost-Benefit Analysis

WordPress Plugin Costs (annually)

ShortPixel:

Starter: 119€/year (10,000 images/month)
Business: 239€/year (30,000 images/month)

Imagify:

Infinite: €119/year (Unlimited)

EWWW Premium:

Executive: €84/year (Unlimited)

In-house development

Development effort:

Basic implementation: 8-16 hours
Testing & optimization: 4-8 hours
Total: €500-1,200 (at €50/hour)

Ongoing Costs:

Server Resources: +10-20% CPU
Storage: +30-50% (3 formats)

ROI Example E-Commerce

Initial Situation:

1,000 visitors/day
Conversion Rate: 2%
Average: 50€ shopping cart value
Bounce Rate: 45%

After WebP Conversion:

PageSpeed: +20 points
Loading time: -1.5 seconds
Bounce rate: -10% (to 35%)
Conversion rate: +0.4% (to 2.4%)

Calculation:

Before: 1,000 × 0.55 × 0.02 × €50 = €550/day
After: 1,000 × 0.65 × 0.024 × €50 = €780/day

Additional revenue: €230/day = €6,900/month
Plugin costs: €119/year = €10/month

ROI: 690:1 (69,000%)

ROI Example Blog

Initial situation:

10,000 visitors/month
Ad revenue: €5 RPM (Revenue per Mille)
Bounce rate: 65%

After AVIF conversion:

PageSpeed: +25 points
Bounce rate: -15% (to 50%)
Page views/visit: +25%

Calculation:

Before: 10,000 × 0.35 × 1.5 × €5/1000 = €26.25/month
After: 10,000 × 0.50 × 1.875 × €5/1000 = €46.88/month

Additional revenue: €20.63/month
Plugin costs: €10/month

Break-even: Immediate
Profit: +€10.63/month

Testing and Monitoring

Test before switching

1. Create a baseline:

PageSpeed Insights: Note Desktop & Mobile Score
Google Analytics: Document loading times
Core Web Vitals: Record LCP, CLS, INP

2. Conduct an A/B test:

50% users WebP/AVIF
50% users JPEG/PNG
Compare metrics

Tools:

Google Optimize (free)
VWO (from $199/month)
Optimizely (Enterprise)

Monitor after the changeover

Google Search Console:

Core Web Vitals → Check for improvements
Page Experience → Track score
Mobile Usability → Identify problems

PageSpeed Insights:

Test most important pages weekly
Track score development

Analytics:

Average load time
Bounce rate
Pages per session
Conversion rate

Testing Checklist

✅ Browser compatibility:

Chrome, Firefox, Safari, Edge tested
iOS Safari, Chrome Android tested
Fallback works in old browsers

✅ Performance:

PageSpeed Score improved
LCP reduced
File size reduced

✅ Functionality:

Images are displayed correctly
Lazy Loading works
Lightbox/Galleries compatible

✅ SEO:

Images indexed in Google Image Search
Structured Data validated
XML Sitemap updated

Future Outlook: JPEG XL and other formats

JPEG XL: The next step?

Properties:

Even better compression than AVIF
Faster encoding
Progressive decoding
Lossless conversion from JPEG

Status (2025):

Chrome: Experimental
Firefox: Behind flag
Safari: No support
Recommendation: Wait and see

WebP 2

Google is working on a WebP successor with:

30% better compression
More modern algorithms
HDR support

Status: Early development phase

Recommendation for the future

2025-2026:

WebP as standard
AVIF for premium content
JPEG as fallback

2027+:

AVIF as the new standard
JPEG XL for special applications
WebP as a legacy fallback

Practical Checklist: Your Step-by-Step Guide

Phase 1: Analysis (Day 1)

[ ] Document current image formats
[ ] Create PageSpeed Insights Baseline
[ ] Determine total size of all images
[ ] Identify most important pages

Phase 2: Strategy (Day 1-2)

[ ] Choose format (WebP, AVIF, or both)
[ ] Decide on plugin or custom solution
[ ] Set budget
[ ] Create rollout plan

Phase 3: Testing (Day 3-5)

[ ] Set up test installation
[ ] Test conversion on 10 sample images
[ ] Check browser compatibility
[ ] Measure performance

Phase 4: Implementation (Day 6-10)

[ ] Install plugin or implement code
[ ] Convert existing images (bulk)
[ ] Activate automatic conversion for new uploads
[ ] Configure caching

Phase 5: Monitoring (Week 2-4)

[ ] Check PageSpeed daily (first week)
[ ] Check Core Web Vitals weekly
[ ] Monitor conversion rate
[ ] Gather user feedback

Phase 6: Optimization (From Week 4)

[ ] Adjust quality settings
[ ] Implement responsive images
[ ] Prioritize critical images
[ ] Create documentation

Conclusion and Recommendation

The clear answer: It depends

Choose WebP if: ✅ You need maximum compatibility ✅ Fast encoding is important (many daily uploads) ✅ You want an established, stable standard ✅ Your hosting has limited CPU resources ✅ You have many older users (B2B, Corporate)

Choose AVIF if: ✅ Performance is an absolute priority ✅ You use high-resolution images ✅ Your target audience uses modern browsers ✅ Fewer, but high-quality images ✅ You are willing to invest more server resources

The optimal hybrid solution for 2025:

<picture>
  <source srcset="bild.avif" type="image/avif">
  <source srcset="bild.webp" type="image/webp">
  <img src="bild.jpg" alt="Optimales Bild" loading="lazy">
</picture>

Why?

AVIF users (88%) get the best quality
WebP users (98%) get good quality
All others (2%) get JPEG fallback
You are future-proof

Quick Wins: Immediately implementable

Install plugin (30 minutes)
- ShortPixel, Imagify or EWWW
- Activate WebP + AVIF
- Start bulk optimization
Activate Lazy Loading (5 minutes)
- Already integrated into WordPress
- Or loading="lazy" for img tags
Use CDN (1 hour)
- Cloudflare free of charge
- Activate Automatic Format Conversion
Responsive Images (2 hours)
- WordPress automatically generates
- Check if theme uses srcset

What you should NOT do

❌ Deliver both formats without fallback ❌ Set quality below 60 (AVIF) / 75 (WebP) ❌ Manually convert all images ❌ Wait for JPEG XL (still too early) ❌ Switch images without testing

Summary: The most important points

WebP:

98% browser support
30% smaller files than JPEG
Fast encoding
Established standard
Perfect for: E-commerce, blogs, corporate

AVIF:

88% browser support
50% smaller files than JPEG
Best image quality
HDR support
Perfect for: portfolios, landing pages, premium content

Hybrid approach:

Best performance for all users
Future-proof
Minimal additional effort with modern tools
Recommended for: Most websites

SEO Impact:

WebP: +15-25% PageSpeed improvement
AVIF: +25-40% PageSpeed improvement
Both: Better Core Web Vitals
Both: Higher ranking potential

Next Steps

Ready for the change? Here are your next actions:

Today: Create PageSpeed Insights Baseline
This Week: Testing with plugin on staging site
Next Week: Rollout on live site
After that: Monitoring and optimization

Do you need support with the implementation or have specific questions about your website? Feel free to contact me!

Florian Ibe
^{CEO & Marketing Consultant}

Request a non-binding consultation now:

fi@vastcob.com

Open contact form

Your contact person: Florian Ibe

About the Author

Florian from VASTCOB is a WordPress developer and WooCommerce specialist with a focus on technical SEO and performance optimization. With over 10 years of experience, he helps e-commerce companies make their websites faster and more successful.

Sources and further information:

Google Web Fundamentals: Image Optimization
Can I Use: WebP / AVIF Browser Support
Cloudinary: State of Visual Media Report 2025
Alliance for Open Media: AVIF Specifications

Florian

has found his calling through passion. Fundamentally honest and direct, he advises everyone from sole proprietors to founders and startups, as well as business and management levels of SMEs. As a consultant, he understands how to reduce complex relationships to their essence and develop a direct message for customers and employees with a sustainable strategy and optimization.