JPG vs PNG vs WebP vs AVIF: which to use

Most image problems people describe as "quality" problems are actually format problems. A screenshot saved as JPG will look smudged and be larger than the same screenshot saved as PNG. Getting the format right does more for your file sizes than any compression setting.

The comparison

• JPG (JPEG) — lossy, no transparency. The universal format: every device, application and upload form accepts it. Ideal for photographs, where its compression is efficient and the losses it makes are the ones the eye notices least.
• PNG — lossless, supports transparency. Ideal for logos, icons, screenshots, charts, anything with flat colour, sharp edges or text. Poorly suited to photographs — a PNG of a photograph is typically three to five times the size of the JPG.
• WebP — supports both lossy and lossless compression plus transparency. Around 25–35% smaller than an equivalent JPG. Supported by all current browsers. Largely superseded by AVIF in terms of raw efficiency, but with broader support across older software.
• AVIF — the newest of the widely deployed formats, built on the AV1 codec. Typically 40–60% smaller than JPG at the same visual quality, with transparency support. Browser support is good but not universal, and older desktop applications often cannot open it.
• GIF — limited to 256 colours, no proper alpha blending. Effectively obsolete except for short animations, where it is slowly being replaced by video.
• SVG — a vector format, defined by mathematical shapes rather than pixels. Perfect for logos and icons at any size, usually a few kilobytes, and it scales without loss. Only a handful of upload systems accept it.

The decision, in one paragraph

Photograph going on a web page? AVIF or WebP, with JPG as a fallback. Photograph going to a person or an upload form? JPG. Logo, icon, screenshot or chart? PNG (or SVG if the recipient accepts it). Anything that needs transparency and broad compatibility? PNG. Animation? Video, not GIF.

Why converting beats compressing

If a screenshot has been saved as JPG, converting it to PNG will often make it both sharper and smaller. The reverse is true for photographs: a 4 MB PNG photograph typically becomes a 600 KB JPG with no visible change. Before you reach for a quality slider, ask whether the format itself is wrong.

The image converter does that conversion in bulk, in your browser. Pick the target format, set the quality for the lossy options, and choose the colour that should replace transparency if you are going to JPG — JPG has no alpha channel, so a transparent logo converted to JPG will fill its background with whatever colour you select.

Serving images on a website

Two rules cover most of the benefit. First, size the image to the largest size it will be displayed at, in pixels, at roughly double density for high-resolution screens. Serving a 4000 px photograph into a 600 px slot is the single most common performance mistake on the web. Second, convert to WebP or AVIF and keep the JPG version for browsers and systems that cannot handle the modern format.

A two-step pipeline does it: use the image compressor to bring the dimensions and quality down to target, then the converter to produce the modern format. Both run locally, so nothing is uploaded and there is no per-file limit to work around.