Image converter
Convert between PNG, JPEG and WebP in your browser, with control over what happens to transparency.
Runs entirely in your browser. Nothing you enter is uploaded.
How this works
What each format is for
The three formats here are not competitors so much as tools for different jobs, and picking by habit rather than by content is the most common mistake.
| Format | Compression | Transparency | Best for |
|---|---|---|---|
| PNG | Lossless | Yes | Screenshots, logos, diagrams, anything with sharp edges |
| JPEG | Lossy | No | Photographs, maximum compatibility |
| WebP | Both | Yes | Almost everything on the modern web |
The rule that catches most cases: if the image has large areas of flat colour and hard edges, use a lossless format. If it is a photograph with continuous gradients, use a lossy one. A screenshot saved as JPEG develops visible smearing around text; a photograph saved as PNG can be five times larger for no visible benefit.
The transparency problem
Converting to JPEG is the one direction that loses information beyond compression. JPEG has no alpha channel, so the question is not whether transparent pixels change but what they change to.
Many converters answer that silently, and the default in a bare canvas is black — which is why a logo with a transparent background so often arrives as a logo on a black rectangle. This tool asks instead, and defaults to white because that is what most documents and web pages sit on. If your logo will be placed on a coloured background, set that colour here and the edges will blend rather than showing a white halo.
Conversions worth avoiding
- JPEG to PNG, expecting improvement. Lossless storage of an already-degraded image preserves the damage perfectly and multiplies the file size. It does not restore anything.
- Repeated lossy round trips. Every JPEG or WebP save discards detail. Converting back and forth a few times produces visible artefacts that nothing can undo. Always start from the highest quality original you have.
- PNG for photographs. Common when a screenshot tool is used to capture a photo. The result is enormous and looks no better.
How the conversion happens here
The image is decoded by the browser, drawn onto a canvas, and re-encoded in the target format — three steps that browsers have supported natively for years. Nothing is transmitted, which means no upload wait, no queue, no file size cap set by someone else's bandwidth bill, and no copy of your image sitting on a server you have never heard of.
One side effect worth knowing: redrawing through a canvas keeps only the pixels. Camera metadata, timestamps, colour profiles and GPS coordinates are not carried across. That is often exactly what you want before publishing an image, but keep the original if any of it matters.
Common questions
- Why did my transparent background turn white?
- Because JPEG has no way to store transparency. Every pixel in a JPEG is opaque, so the transparent areas have to become some colour. This tool lets you pick which one and defaults to white; without that step they would come out black, which is the usual unpleasant surprise. If you need the transparency, convert to PNG or WebP instead.
- Can it convert HEIC files from my iPhone?
- Only if your browser can decode HEIC, which Safari on Apple devices can and most others cannot. Where the browser can read the file, conversion works normally. Where it cannot, the file will fail to load — there is no way for a page to decode a format the browser does not support without shipping a large decoder library.
- Does converting lose quality?
- It depends on the direction. PNG to WebP or JPEG is lossy, so some detail is discarded. JPEG to PNG is lossless but does not recover anything already lost — you get an exact copy of the degraded image in a larger file. WebP to JPEG re-encodes lossy data that was already lossy, which compounds the loss slightly.
- Which formats can my browser write?
- The tool checks at load and only offers what actually works. Browsers silently fall back to PNG when asked for a format they cannot encode, which would otherwise produce a file with the wrong extension, so the check happens before you choose rather than after.
- Is there a file size limit?
- Only what your device can hold in memory. Because there is no upload, there is no server limit and no queue. Very large images — well beyond 50 megapixels — may be slow or may fail on a phone with little free memory.