JPG vs PNG vs WebP vs AVIF: Which Format Should You Use?
A plain-language comparison of the four most common image formats — what each is actually good at, and when picking the wrong one costs you file size or quality.
Every image format is a tradeoff between file size, quality, and compatibility. Picking the wrong one for the job is one of the most common reasons files end up too big or don't upload where they're supposed to.
JPG (JPEG)
JPG is lossy — it throws away detail to save space, and it's very good at that specifically for photos: continuous tones, lots of colors, no sharp edges. It's the format almost every form, portal, and ID requirement expects for photographs, and it's what basically every phone camera and scanner defaults to.
Weak spot: sharp edges and text look noticeably worse in JPG than in a lossless format — a screenshot of text saved as JPG often shows visible fuzzing around letters.
PNG
PNG is lossless — nothing is thrown away, so quality is perfect, but file sizes are much bigger for photographic content. It's the right choice for screenshots, logos, diagrams, and anything with flat colors or sharp text, and it supports transparency (which JPG doesn't).
Weak spot: a PNG of an actual photo is routinely 3–5x larger than the same photo saved as JPG, for no visible quality benefit — most photo requirements explicitly reject PNG for exactly this reason.
WebP
WebP is Google's newer format, supporting both lossy and lossless modes, and it generally beats both JPG and PNG at their own game — smaller files at equivalent quality. Browser support is now essentially universal.
Weak spot: some older forms, portals, and government systems still don't accept it as an upload format, even though your browser displays it fine. Worth converting to JPG before uploading anywhere with strict format rules.
AVIF
AVIF is the newest of the four, and generally the smallest file for a given quality level — often noticeably smaller than WebP for photographic content. It's increasingly common as a default output from newer cameras and export tools.
Weak spot: acceptance is the narrowest of the four — most upload forms, portals, and older software don't recognize it at all.
The practical rule
For anything you're uploading to a form, portal, or ID system: JPG, unless the form explicitly says otherwise. It's the one format every system reliably accepts, and it's built for exactly the kind of photographic content most of these requirements are asking for.
For anything staying on your own device or website: WebP or AVIF give you real size savings with no visible quality loss, if the destination supports them.