Start with the destination, not the format
Almost every “what format should I use?” argument disappears once you name the destination. A print shop wants every pixel preserved and does not care about file size. A website wants the smallest file that still looks right. An upload form wants whatever its developer decided to accept a decade ago, and a piece of industrial or point-of-sale software may want something genuinely ancient. Those are four different answers, and none of them is wrong.
So before converting anything, finish this sentence: “this file needs to open in ___.” The rest of this guide is that answer, format by format.
For the web: AVIF, WebP, then JPG
For images you are putting on a site, smaller is better as long as the picture still looks clean. AVIF produces the smallest files of anything here and keeps transparency, which makes it the strongest choice for photos and hero images on a modern site. WebP is slightly larger but has been supported everywhere for years, so it is the safer default. JPG remains the universal fallback: every browser, email client, and CMS made this century accepts it.
Two practical notes. AVIF is encoded by a WebAssembly encoder that downloads once (about 3.4 MB) the first time you pick it, and it is the slowest format to encode — fine for a handful of hero images, slow for hundreds. And JPG has no transparency, so anything see-through is flattened onto white.
For print and archiving: TIFF or PNG
Print shops and archives want lossless files, meaning nothing is thrown away to save space. TIFF is the traditional answer and is what most print workflows and scanners expect. Its one catch is that browsers cannot display TIFF, so the file will not preview in a browser tab — that is normal, not a failed conversion.
PNG is the other lossless option and the more practical one if the file also needs to be viewed, emailed, or dropped into a document. It keeps transparency and opens everywhere. Choose TIFF when a printer explicitly asks for it; choose PNG the rest of the time.
For old software and icons: BMP, GIF, ICO
These three exist for specific, narrow jobs. BMP is uncompressed, so files balloon dramatically — a small image can land in the megabytes. Convert to BMP only when some legacy Windows program refuses everything else. GIF is limited to 256 colors and, in this converter, is a single still frame with no transparency; it suits flat graphics and logos, and will visibly band on photographs. ICO is the Windows icon container: square, capped at 256 pixels, bundling the 16, 32, 48 and 256 px sizes that fit your source.
If what you actually want is a complete favicon set — the .ico plus the apple-touch-icon, the manifest PNGs and the HTML snippet — the dedicated Favicon Generator on this site produces all of it in one step rather than just the single .ico file.
Converting, without uploading anything
- Open the Image Converter and pick your target format from the “Convert to” menu. Each option shows a one-line summary of its trade-off, so you can sanity-check the choice before converting.
- Drop your images on the dropzone. There is no cap on how many you add and no sign-up; three convert in parallel while the rest wait their turn.
- Check the before and after sizes on each row, then download files individually or take the whole batch as one ZIP.
Every step runs inside your browser tab using a Web Worker — the images are never uploaded, so client work, scanned paperwork and personal photos stay on your machine. If you always run the same pair, the dedicated pages such as PNG to ICO or JPG to TIFF do the same job with both formats pre-selected.