Image Format Guide: JPEG vs PNG vs WebP Comparison
1. Image Formats at a Glance
Web image formats fall into two categories: raster (bitmap) and vector. This guide compares the most common raster formats: JPEG, PNG, WebP, and AVIF.
| Format | Compression | Transparency | Animation | Browser Support |
|---|---|---|---|---|
| JPEG | Lossy | No | No | 100% |
| PNG | Lossless | Yes | APNG | 100% |
| WebP | Both | Yes | Yes | ~97% |
| AVIF | Both | Yes | Yes | ~92% |
| GIF | Lossless (256 colors) | Yes (1-bit) | Yes | 100% |
2. JPEG: Best for Photos
JPEG (Joint Photographic Experts Group) dates back to 1992 and remains the most widely used image format on the web. It excels at compressing photographs and complex images to small file sizes.
JPEG Strengths
- Excellent compression for photos (10-20x size reduction possible)
- Universal support across every browser and device
- Quality level adjustable from 0-100% for fine-grained control
JPEG Weaknesses
- No transparency support (no alpha channel)
- Artifacts appear around sharp edges like text, lines, and logos
- Quality degrades each time you re-save (generation loss)
A JPEG quality setting of 75-85% provides the best balance. Files shrink significantly while remaining visually indistinguishable from the original for most viewers.
3. PNG: Transparency and Sharpness
PNG (Portable Network Graphics) uses lossless compression, preserving every pixel perfectly. It supports full alpha channel transparency, making it ideal for graphics that need transparent backgrounds.
PNG-8 vs PNG-24
| Feature | PNG-8 | PNG-24 |
|---|---|---|
| Colors | 256 | 16 million+ |
| File size | Small | Large |
| Transparency | 1-bit (on/off) | 8-bit alpha |
| Best for | Icons, simple graphics | Logos, UI elements |
PNG is inefficient for photos. The same photograph might be 200KB as JPEG but 2MB as PNG. Reserve PNG for logos, icons, screenshots, and images with text overlays.
4. WebP: The Modern Web Standard
WebP was developed by Google in 2010 and combines the best of JPEG and PNG. It supports both lossy and lossless compression, transparency, and animation in a single format.
WebP File Size Comparison
- Photos: 25-35% smaller than JPEG at equivalent quality
- Graphics: 26% smaller than PNG in lossless mode
- Animation: Up to 64% smaller than equivalent GIF
AVIF: The Newer Alternative
AVIF offers even better compression than WebP but has slower encoding speeds and slightly lower browser support. As of 2026, most major browsers support it, but older devices may need a fallback.
5. Choosing the Right Format
JPEG
- Photographs, landscapes
- Social media sharing
- Email attachments
- No transparency needed
PNG
- Logos, icons
- Transparent backgrounds
- Screenshots, diagrams
- Images with text
WebP
- General website images
- Performance-critical pages
- Transparency + small size
- JPEG/PNG replacement
AVIF
- Maximum compression needed
- HDR images
- Modern browsers only
- Build time is not a concern
Convert Your Images
Easily convert between JPEG, PNG, WebP, and more image formats.
Use Image Converter →6. Web Image Optimization Tips
Serve Responsive Images
Use HTML srcset and sizes attributes to serve appropriately sized images for each device. This prevents mobile users from downloading desktop-sized images, saving data and load time.
Apply Lazy Loading
Defer loading of off-screen images with lazy loading. Simply add loading="lazy" to your img tags. This significantly improves initial page load performance, especially on image-heavy pages.
Use a CDN
CDNs like Cloudflare or AWS CloudFront serve images from the server closest to the user, reducing latency. Many CDNs also offer automatic WebP/AVIF conversion and resizing on the fly.
Performance Target
Aim for hero images under 200KB and thumbnails under 50KB for Google PageSpeed. Keep Largest Contentful Paint (LCP) under 2.5 seconds for good Core Web Vitals scores.