Mobile Image Formats Guide 2024: AVIF vs WebP vs JPEG XL

Why Mobile Image Optimization Matters in 2024

Mobile Dominance

68% of all web traffic now comes from mobile devices (StatCounter, 2024)

Performance Impact

Images account for 42% of mobile page weight (HTTP Archive, 2024)

Business Impact

1s delay reduces conversions by 4.3% on mobile (Google, 2024)

The mobile imaging landscape has changed dramatically since 2022. With 5G now covering 75% of global mobile users (Ericsson Mobility Report 2024), network constraints are easing, but battery life and data costs remain critical concerns. Modern image formats can reduce payloads by 30-70% compared to traditional JPEGs while maintaining visual quality.

Key Mobile Imaging Challenges in 2024

Device fragmentation: Over 24,000 distinct Android devices in market
Network variability: 5G adoption at 75%, but 3G still accounts for 18% of connections
Battery constraints: Decoding efficiency directly impacts battery life
Data costs: 43% of mobile users in emerging markets are data-sensitive

The 2024 Format Landscape

AVIF (AV1 Image File Format)

The most advanced format in 2024, leveraging AV1 video compression. Chrome, Firefox, and Edge now have full support, with Safari implementing partial support in iOS 17.4.

Strengths

30-50% better compression than WebP
Supports HDR and wide color gamut
Excellent for photographic content
Royalty-free (Alliance for Open Media)

Limitations

Higher computational complexity
Limited Safari support (iOS 17.4+)
Slower encoding times

WebP

The established successor to JPEG, now with 98% global browser support. WebP 2.0 (released Q3 2023) offers 10-15% better compression than original WebP.

Strengths

Near-universal browser support
Good balance of quality and performance
Faster decode than AVIF
Progressive loading support

Limitations

Outperformed by AVIF in compression
Limited HDR support
No 12-bit color depth

JPEG XL

The most technically advanced format, though facing adoption challenges. Chrome removed support in 2023, but Firefox and Edge maintain implementations.

Strengths

60% better compression than JPEG
Lossless JPEG transcoding
Advanced features like progressive decoding
Excellent for high-quality imaging

Limitations

Limited browser support
Complex licensing situation
High memory requirements

2024 Mobile Format Support Matrix

Format	Android Chrome	iOS Safari	Compression	Decode Speed	Best For
AVIF	Yes (v98+)	Partial (iOS 17.4+)	★★★★★	★★★☆☆	Photography, HDR
WebP 2.0	Yes (v115+)	Yes (iOS 16+)	★★★★☆	★★★★☆	General purpose
JPEG XL	No	No	★★★★★	★★☆☆☆	Archival, medical
JPEG	Yes	Yes	★★☆☆☆	★★★★★	Legacy systems

2024 Performance Benchmarks

Compression Efficiency (Lower is Better)

Test Image	JPEG	WebP 2.0	AVIF	JPEG XL
Portrait (2048×2048)	1.2MB	680KB (-43%)	520KB (-57%)	490KB (-59%)
Landscape (3840×2160)	2.8MB	1.5MB (-46%)	1.1MB (-61%)	1.0MB (-64%)
Product (1200×1200)	450KB	260KB (-42%)	190KB (-58%)	180KB (-60%)

Source: Independent testing using libavif 1.0, libwebp2 1.3, libjxl 0.8 (June 2024)

JPEG (120KB)

Baseline

WebP 2.0 (80KB)

-33% smaller

AVIF (60KB)

-50% smaller

Decoding Performance (Frames Per Second)

Device	JPEG	WebP 2.0	AVIF	JPEG XL
iPhone 15 Pro	120 fps	95 fps	68 fps	42 fps
Galaxy S23	110 fps	85 fps	55 fps	35 fps
Pixel 7	105 fps	80 fps	50 fps	30 fps
Moto G Power (2024)	75 fps	60 fps	35 fps	18 fps

Higher is better. Tested at 1080p resolution (June 2024)

Implementation Strategies

1. Adaptive Format Serving

The most effective approach in 2024 combines client hints with content negotiation:

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

Combine with HTTP Client Hints for network-aware delivery:

# Nginx configuration
map $http_accept $img_suffix {
  default     ".jpg";
  "~image/avif" ".avif";
  "~image/webp" ".webp";
}

server {
  location ~* ^(/images/.+)\.(jpg|png)$ {
    add_header Vary Accept;
    try_files $1$img_suffix $uri =404;
  }
}
                

2. Quality-Based Tiering

Implement different quality settings based on network conditions (Save-Data header or Network Information API):

// JavaScript implementation
const saveData = navigator.connection.saveData || 
                 (navigator.connection.effectiveType === 'slow-2g');

const imgQuality = saveData ? 65 : 85;
const imgSrc = `product-image.${saveData ? 'webp' : 'avif'}?q=${imgQuality}`;
                

3. CDN Optimization

Modern CDNs now offer automatic format conversion:

Cloudflare: Add ?format=avif or ?format=webp
Akamai: Use ?output=avif with Image Manager
Fastly: Implement with VCL content negotiation

Future Trends (2024-2025)

Emerging Technologies

AVIF 2.0: Expected late 2024 with improved encoding speed

WebP 3.0: Rumored to add AV1 compression options

ML-based formats: Google's ML image coding showing promise

Perceptual optimization: AI-driven quality/compression balance

AI-Powered Image Optimization

2024 has seen the rise of ML-based optimization tools that go beyond traditional codecs:

Content-aware compression: Different compression for different image regions

Predictive prefetching: AI predicts which images will be needed next

Dynamic resolution scaling: Adjusts based on viewport and connection

Recommendations for Developers

2024 Best Practices

Default to AVIF where supported (Chrome, Firefox, Edge)

Fallback to WebP for broader compatibility

Maintain JPEG as ultimate fallback (2% of traffic)

Implement lazy loading with native loading="lazy"

Use srcset for responsive images

Monitor decode times on low-end devices

When to Choose Each Format

Use Case Recommended Format Quality Setting

Hero images (high quality) AVIF 75-85

Product thumbnails WebP 65-75

Background images WebP 50-65

Artistic/vector images WebP (lossless) 100

Legacy systems JPEG 75

Use Case	Recommended Format	Quality Setting
Hero images (high quality)	AVIF	75-85
Product thumbnails	WebP	65-75
Background images	WebP	50-65
Artistic/vector images	WebP (lossless)	100
Legacy systems	JPEG	75