Choosing a format instead of defaulting to one
An image converter decodes a picture from one file format and re-encodes it in another, changing how the pixels are stored — and, depending on the target format, whether transparency, animation and colour depth survive.
Format choice is the optimisation people skip because every format basically works. But the gap between the right and wrong format for a given image is large: a screenshot saved as JPEG looks fuzzy and is bigger than the PNG would have been, while a photograph saved as PNG can be five times the size of an equivalent WebP.
This converter supports JPEG, PNG, WebP, GIF and TIFF. This page sets out what each format is genuinely good at, what is lost in the conversions that lose something, and the one conversion you should think twice about.
What each format is actually for
Direct answer: WebP for photographs on the web, PNG for graphics with flat colour or transparency, JPEG when something old needs to read the file, and TIFF only for print and archival handoff.
| Format | Compression | Transparency | Best for |
|---|---|---|---|
| JPEG | Lossy | No | Photographs where universal compatibility matters more than the last 30% of file size. |
| PNG | Lossless | Yes, with full alpha | Logos, icons, screenshots, diagrams — anything with sharp edges, text or flat colour. |
| WebP | Lossy or lossless | Yes | The default for web photographs today. Typically 25–35% smaller than JPEG at similar perceived quality, and supported by every current browser. |
| GIF | Lossless, 256 colours | Yes, but only fully on or off | Legacy animation. For anything photographic it is the worst option available — the palette limit destroys gradients. |
| TIFF | Usually uncompressed or lossless | Yes | Print production and archival masters. Very large files; not for the web. |
Conversions that lose something permanently
Converting between formats is not always reversible. These are the cases where information does not survive the trip.
PNG to JPEG destroys transparency
JPEG has no alpha channel. Transparent regions are flattened onto a solid background, which shows up as a white or black box the moment the image sits on a coloured surface. Convert to WebP instead if you need both transparency and small files.
Anything to GIF crushes the colours
GIF supports 256 colours per frame. A photograph converted to GIF will show visible banding in every gradient, and the file will usually be larger than the JPEG you started with.
JPEG to PNG does not restore quality
Converting a lossy file to a lossless one preserves the artefacts perfectly and makes the file much bigger. There is no upside unless you are about to edit the image and want to avoid further generational loss.
Animation does not survive
Converting an animated GIF to a still format keeps one frame. For animation on the web, an MP4 or WebM video is dramatically smaller than a GIF anyway.
Metadata may not carry over
EXIF data — camera settings, capture date, GPS coordinates — is not guaranteed to survive a format change. That is a privacy benefit when publishing photos and a loss when cataloguing them, so keep the originals.
Colour profiles
Images in a wide-gamut profile can shift in appearance when converted for the web. If precise colour matters, convert to sRGB deliberately in an editor rather than relying on a format change.
A decision procedure that takes ten seconds
- 1
Does the image need transparency?
If yes, the choice is PNG or WebP. JPEG is out regardless of everything else.
- 2
Is it a photograph or a graphic?
Continuous tone — a photo — goes to WebP or JPEG. Flat colour, text or sharp edges goes to PNG or lossless WebP.
- 3
Who has to open it?
For the web, WebP is safe on every current browser. For an email attachment, a client’s legacy system or a print supplier, JPEG or TIFF is the safer handoff.
- 4
Convert, then compress
Format conversion sets the ceiling; compression finds the floor. Follow up with the image compressor once the format is right.
- 5
Check the result at full size
Look for banding in skies, halos around text and lost transparency before you publish. A thumbnail hides all three.
Conversion runs on our server: the file is uploaded over HTTPS, re-encoded in memory and returned, with a 10 MB limit per image and no retention after the response.
Preparing an image for the web, end to end
- Crop first — removed pixels cost nothing to serve.
- Resize to display dimensions with the image resizer, doubled for high-density screens.
- Convert photographs to WebP; keep flat graphics and anything with transparency as PNG.
- Compress at 75–85 for photographic content and inspect the result at full size.
- Give every image descriptive alt text — it is an accessibility requirement and an SEO signal, and screen-reader users depend on it.
- Set explicit width and height attributes so the browser reserves space and your layout does not shift while loading.
How this page is maintained
The supported output formats and the server-side conversion path described here were read from this tool’s implementation. Format characteristics follow each specification; the WebP size comparison is stated as a typical range because actual savings depend heavily on the source image.
Written and reviewed by the ToolsRacks editorial team. Last reviewed: .