This image format comparison guide covers the five formats you'll actually run into day to day — what each one is built for, where it falls short, and how to tell which one you're holding. No format is universally "best"; each one is a different set of tradeoffs between file size, quality, compatibility, and features like transparency.
JPEG — the universal default
The oldest and most broadly compatible format on this list. Lossy compression (some detail is discarded to shrink the file), no transparency support, but it opens absolutely everywhere — every browser, every OS, every piece of software from the last several decades. Best for: photos that need to work anywhere without a second thought.
PNG — lossless, with transparency
PNG doesn't discard any image data — what you save is exactly what you get back, with no quality loss. It also supports transparency, which JPEG doesn't. The tradeoff is file size: PNG's lossless compression doesn't shrink photographic detail nearly as efficiently as lossy formats do, so photos saved as PNG tend to be much larger than necessary. Best for: logos, icons, screenshots, and graphics with sharp edges or flat color — not photos.
WebP — a modern, more efficient default
Built specifically to improve on JPEG and PNG at once: typically a quarter to a third smaller than an equivalent-quality JPEG, while also supporting transparency like PNG. Broadly supported across every current browser. For most everyday images going onto a website today, WebP is the more efficient choice over either JPEG or PNG. Best for: general-purpose web images — it replaces both JPEG and PNG for the majority of use cases.
AVIF — smaller still, at the cost of encode time
AVIF pushes compression further than WebP, using techniques derived from the AV1 video codec. It typically produces smaller files than WebP at the same visual quality — but encoding an AVIF file takes noticeably longer than encoding the equivalent WebP or JPEG. That cost is one-time, not per-visitor, which makes it worth it for high-traffic, photo-heavy pages where every kilobyte affects load time. Best for: performance-critical websites willing to trade encode time for smaller delivered files.
HEIC — Apple's efficient default, with a compatibility catch
HEIC is what iPhones save photos as by default, using compression similar in spirit to AVIF's approach — smaller files than JPEG at comparable quality. The catch is compatibility: plenty of software, older systems, and non-Apple devices don't open it directly, which is why "why won't this photo open on Windows" is such a common complaint. Best for: staying on Apple devices; convert to JPEG the moment a photo needs to leave them.
Quick reference
| Format | Compression | Transparency | Best for |
|---|---|---|---|
| JPEG | Lossy | No | Maximum compatibility |
| PNG | Lossless | Yes | Logos, graphics, screenshots |
| WebP | Lossy (with lossless option) | Yes | General web images (modern default) |
| AVIF | Lossy | Yes | High-performance web images |
| HEIC | Lossy | No | iPhone photos, staying on Apple devices |
Converting between formats
Whatever direction you need to go — HEIC to JPEG, PNG to WebP, JPEG to AVIF, or anything else — the format converter handles it directly in your browser, with no upload involved. A few dedicated shortcuts if you know exactly what you need:
- HEIC to JPG — for iPhone photos that won't open elsewhere
- PNG to WebP — for shrinking web graphics without losing transparency
- JPG to AVIF — for squeezing out maximum web performance
The short version
Need it to work everywhere, no exceptions? JPEG. Need transparency and zero quality loss? PNG. Building a modern website and want the best general-purpose default? WebP. Optimizing hard for page speed? AVIF. Shooting on an iPhone and keeping photos on Apple devices? HEIC. Just convert before a photo needs to leave.