Image Format Converter

Features

• Six output formats: PNG, JPEG, WebP, AVIF, BMP and TIFF
• Five quality steps from 95% to 60% (lossless formats ignore it)
• A background colour is laid down before JPEG and BMP conversion, so transparency never turns black
• Limit the longest edge to 2560, 1920, 1280, 800 or 512 pixels
• Shows the size change, e.g. 12.3 MB → 2.1 MB (−83%)
• AVIF encoding is feature-detected, and an unsupported browser is told so — never a PNG wearing an .avif extension
• BMP is a hand-written encoder (24-bit, uncompressed) and TIFF is written uncompressed — browsers cannot produce either natively
• TIFF input is decoded in the browser, which has no native reader for it (scans often arrive as TIFF)
• Drop a file, pick one, or paste a screenshot with Ctrl/⌘ + V
• Nothing is uploaded and no server is involved — it works offline

How to use

1. Drop an image above, click to choose, or paste a screenshot
2. Pick the output format, quality and size limit
3. The result appears at once with the size change (BMP and TIFF grow a lot — that is the format)
4. Click Download, or right-click the preview to save it

FAQ

Transparent areas turned black when I converted to JPEG. Why?

That is inherent to JPEG — it has no transparency channel, so transparent pixels must be filled with some colour, and canvas fills them black by default. This tool lays down a background first (white by default; black and off-white are options), so you get a white background instead. To keep transparency, stay with PNG or WebP.

Which of the three should I pick?

WebP for photographs (typically 25–35% smaller than JPEG at the same quality, and every current browser reads it); JPEG when compatibility matters most (email attachments, older software); PNG for flat colours, screenshots and transparency. Icons and line art look far better as PNG or WebP — JPEG produces fringing around sharp edges.

What quality setting is reasonable?

85% is the usual sweet spot: much smaller than 95% with almost no visible difference. 92% is the default for detail-heavy images. 60% is for when the content matters more than the appearance (showing a colleague what a screenshot says). Quality only affects JPEG and WebP — PNG is lossless and ignores it.

Is the image uploaded?

No. Decoding uses the browser's own createImageBitmap and encoding uses canvas, all in local memory — images are often private photos or screenshots with client details, and none of it leaves the machine. The tool keeps working with the network off, which is the proof that nothing is being sent.

I picked AVIF and it says my browser cannot encode it. Why?

Because that is true — Chrome and recent Edge can encode AVIF, while Firefox so far can only decode it, as can older Safari. This tool does not silently "downgrade" you to another format, and does not hand back a PNG with a renamed extension. That last part matters most: `canvas.toBlob` already falls back to PNG on its own when given a format it cannot produce, and the resulting blob reports its type as `image/png` — so "it produced AVIF" and "it actually produced a PNG" are identical in code. The test here is therefore a real one-pixel encode followed by a check on the result type, not a lookup in a support table. Use Chrome or a recent Edge if you need AVIF; otherwise WebP is the safer choice.

The BMP or TIFF came out ten times larger. Is that expected?

Yes, and it has to be — neither format compresses. A BMP is three bytes per pixel, each row padded to a multiple of four, plus a 54-byte header; the TIFF written here is uncompressed too. A 500 KB JPEG expands to its full raw pixel data, and that is the size it takes. These formats exist for software that only opens one of them, and for print shops that ask for TIFF. They are not for saving space. Pick WebP for that.

Can it open HEIC photos from an iPhone?

It depends on the browser. Safari, and Chrome on Android and macOS, usually read them; Firefox and desktop Chrome generally do not. This site does not load a 2 MB WASM decoder for it — that would weigh down the first paint of every image tool in exchange for one input direction (and HEIC cannot be encoded here at all). When it fails, the page says the browser cannot read the file rather than a vague "decode failed": on an iPhone use "Export as JPEG", and elsewhere open it in your image viewer and save a copy as JPEG or PNG first.