Choosing the right image format is the single most important decision in image optimization. Use the wrong format and you'll either have bloated files or visible quality loss — sometimes both. This guide compares JPEG, PNG, WebP, AVIF, and HEIC across every dimension that matters: file size, quality, transparency, browser support, and best use cases.
Format Comparison at a Glance
| Feature | JPEG | PNG | WebP | AVIF | HEIC |
|---|---|---|---|---|---|
| Compression Type | Lossy | Lossless | Both | Both | Both |
| Transparency | ❌ No | [OK] Yes | [OK] Yes | [OK] Yes | [OK] Yes |
| Animation | ❌ No | ❌ No (APNG exists) | [OK] Yes | [OK] Yes | ❌ No |
| Relative Size* | 1.0× (baseline) | 3-10× larger | 0.65-0.75× | 0.45-0.55× | 0.5-0.7× |
| Max Color Depth | 8-bit (16.7M) | 8-bit / 16-bit | 8-bit | 12-bit | 16-bit |
| HDR Support | ❌ No | ❌ No | ❌ No | [OK] Yes | [OK] Yes |
| Browser Support | 100% | 100% | ~97% | ~93% | Safari only |
| Best For | Photos, web | Logos, icons, UI | Modern web | Next-gen web | Apple ecosystem |
* Relative size for the same photographic image at equivalent visual quality. JPEG at quality 85 = baseline 1.0×.
JPEG: The Universal Workhorse
JPEG (Joint Photographic Experts Group) has been the standard for photographic images since 1992 — and for good reason. It offers excellent compression for photos with universal compatibility. Every browser, every app, every device supports JPEG.
When to Use JPEG
- Photographs and photo-realistic images
- Web images where universal compatibility is paramount
- Email attachments (every email client displays JPEG)
- Social media uploads
When NOT to Use JPEG
- Logos or icons with sharp edges (compression artifacts are visible)
- Images with text (text becomes blurry in JPEG)
- Images requiring transparency (JPEG doesn't support it)
- Screenshots of UI (PNG is much better for this)
PNG: The Graphics Specialist
PNG (Portable Network Graphics) uses lossless compression — every pixel is preserved exactly. This makes it perfect for graphics, logos, and text, but terrible for photographs where file sizes balloon to 3-10× the JPEG equivalent.
When to Use PNG
- Logos and brand marks
- Icons and UI elements
- Screenshots (especially of text-heavy interfaces)
- Images requiring transparent backgrounds
- Graphics with sharp edges and solid colors
When NOT to Use PNG
- Photographs (use JPEG or WebP — files will be 5-10× smaller)
- Large hero images (PNG will be megabytes)
- Email attachments (JPEG is much smaller for photos)
WebP: The Modern All-Rounder
Developed by Google and released in 2010, WebP has become the best general-purpose web image format. It supports both lossy and lossless compression, transparency, and animation — all at file sizes 25-35% smaller than JPEG and 25% smaller than PNG.
When to Use WebP
- Website images (WordPress, Shopify, and most CMS platforms support it)
- Anywhere you currently use JPEG — WebP will be smaller at the same quality
- Animated images (as a replacement for GIF)
- Images with transparency that need smaller files than PNG
When NOT to Use WebP
- Email (most email clients don't display WebP)
- Apps that don't explicitly support it
- When you need 100% browser compatibility
AVIF: The Future
AVIF (AV1 Image File Format) is the newest contender, offering 20-30% smaller files than WebP at equivalent quality, plus HDR support and 12-bit color depth. It's the best format technically — but browser support is still catching up.
When to Use AVIF
- Cutting-edge web projects where you can serve fallback formats
- HDR image delivery
- When every byte counts (mobile-first experiences)
When NOT to Use AVIF
- Safari versions before 16 (use WebP fallback)
- Email, social media, or any context where compatibility matters more than size
HEIC: The iPhone Native
HEIC (High Efficiency Image Container) is Apple's default photo format since iOS 11. It offers excellent compression (50% smaller than JPEG) but has virtually no web browser support outside Safari. For web use, always convert HEIC to JPEG or WebP.
Which Format Should You Use? Decision Guide
- Is it a photo for the web? → Use WebP with JPEG fallback, or JPEG for simplicity.
- Is it a logo, icon, or graphic with transparency? → Use PNG. Consider WebP if you need smaller files.
- Is it for email? → Use JPEG. Email clients don't support WebP.
- Is it for a cutting-edge web project? → Use AVIF with WebP/JPEG fallback.
- Is it from an iPhone? → Convert HEIC to JPEG or WebP before using on the web.
You can convert between all these formats using our free image format converter — no upload, 100% browser-based.