JPG vs PNG vs WebP vs AVIF: Which Image Format Should You Use?

All four formats store raster images, but they make different compromises. Lossy compression discards some image information to reduce size. Lossless compression reconstructs the encoded pixels exactly, although it cannot restore detail that was already removed before the file was created. Alpha support determines whether pixels can be partly or fully transparent. Animation support determines whether a file can contain a sequence of frames rather than one still image.

Compatibility is more than whether a current browser can display a file. A format may also pass through content-management systems, email clients, design tools, app stores or older devices. For public web delivery, test the browsers and downstream software that actually matter and provide a fallback when that audience requires one.

JPG is still appropriate for ordinary photographs when a simple file, fast decoding and very broad software support matter. It has no alpha channel, so transparent pixels need a chosen background. Strong compression can create block, ringing or smearing artifacts around edges. Saving a JPG repeatedly can add new loss because each lossy encode starts from pixels that may already contain artifacts.

PNG is appropriate for screenshots, interface captures, diagrams, logos and line art when exact edges or alpha transparency matter. Its lossless compression is predictable for flat colors and repeated patterns, but photographic PNG files can be much larger than sensible lossy alternatives. PNG is not automatically higher quality than the source: converting a damaged JPG to PNG preserves the decoded damage rather than recovering the discarded detail.

WebP is useful when one format must cover photographs, transparent graphics or animation with current-browser support. The encoder can use lossy or lossless mode, so the extension alone does not describe the quality decision. AVIF is useful when efficient compression, alpha, higher bit depth or modern delivery features justify its encoding cost and compatibility checks. Neither format should be selected only because it is newer.

A transparent logo cannot be represented faithfully as JPG without compositing it onto a background. PNG, WebP and AVIF can carry alpha, but a converter must preserve that channel and the destination system must accept it. A file that looks correct on a white page can still contain unwanted edge colors when placed over a dark background, so test the output on more than one surface.

Animation is also a file-level feature. WebP and AVIF can represent multiple images, while baseline JPG is a still format and ordinary PNG is distinct from APNG. A still-image converter may intentionally use only the first frame. Check the tool's stated behavior before converting an animated source; a successful download does not prove that every frame survived.

EXIF, camera details, color profiles, location fields and editing metadata are independent of visible pixels. Browser-created outputs do not necessarily retain all metadata. Removing metadata can be desirable for privacy, but it can also discard orientation, attribution or color information that a workflow depends on. Keep the original and inspect the exported file when metadata is important.

Start from the best available original, resize only when the delivered dimensions can be smaller, and compare output at the size people will actually view. File size is not a quality score: a larger file can be wasteful, while a very small file can contain visible artifacts. For lossy formats, try a representative quality setting and inspect faces, gradients, text, fine lines and high-contrast edges.

Avoid chains such as JPG to WebP to JPG. Every lossy stage may introduce another generation of error. If several outputs are needed, create each one from the original master. For websites that need a newer format and a conservative fallback, the HTML picture element can let the browser select a supported source while retaining a regular img fallback.

Current major browsers support these common web formats, but historical browser depth and non-browser software vary. MDN's compatibility tables are a better source for current browser versions than a permanent claim written into a page. Test upload validators, social platforms, document editors and native apps separately because browser support does not guarantee that those systems accept the same files.

When uncertainty is expensive, keep a JPG or PNG fallback and measure the actual files produced by the chosen encoder. Format capability, encoder quality, decoder behavior and the source image all affect the result. The most useful choice is the one that meets the required visual features, compatibility and transfer budget together.