🔄 Image Converter
Convert between JPG, PNG and WebP with control over the background colour behind transparency. Batch, size comparison, and nothing is uploaded to a server.
Choose images, or drop them here
Converted in this tab — nothing is uploaded to a server.
Settings apply to the next file you add. 90 is visually lossless for almost any photograph.
What Image Converter Does
Converting between image formats is decode-then-re-encode: the file is turned back into a grid of pixels and written out under a different set of rules. Nothing about the picture is preserved by magic, and the interesting question in every conversion is what the destination format cannot hold.
For JPG the answer is transparency. JPEG has no alpha channel at all — it stores three colour components per pixel and that is the whole format. So converting a transparent PNG to JPG forces a decision about what the transparent pixels become, and a converter that does not make that decision deliberately hands you black, because an untouched canvas is transparent black and the encoder simply drops the alpha. That is the black box people find around their logo. Here the background is a control.
For PNG the answer is that lossless does not mean recovered. PNG will not throw anything further away, but it cannot restore what a JPG already discarded — you get a file several times larger containing the same visible information, with the JPEG artefacts now preserved perfectly.
WebP is the format worth defaulting to when the destination allows it. Google’s own compression study measured it 25 to 34 percent smaller than JPEG at equal or slightly better SSIM, and unlike JPEG it keeps an alpha channel.
How to Use Image Converter
- Choose the output format — JPG, PNG or WebP
- If you picked JPG, set the colour that should replace any transparency
- Set the quality, then add your images or drop them onto the box
- Check the before-and-after sizes and save individually or all at once
What each format can and cannot hold
The row that decides most conversions is transparency, and the row that decides the rest is how the format compresses.
| Format | Compression | Alpha | Animation | Typical size, same photo |
|---|---|---|---|---|
| JPG | Lossy (DCT) | No | No | Baseline |
| PNG | Lossless (DEFLATE) | Yes, 8-bit | No | 3–6× larger |
| WebP | Lossy or lossless | Yes, 8-bit | Yes | 25–34% smaller than JPEG at equal SSIM |
| GIF | Lossless, 256-colour palette | 1-bit only | Yes | Much larger, and posterised |
Source: Google — WebP Compression Study
Choosing the destination
| What you have | Where it is going | Convert to |
|---|---|---|
| A photograph as PNG | Email, upload, anywhere size matters | JPG — often 5–10× smaller with no visible loss |
| A logo with a transparent background | A website | WebP — keeps transparency, smaller than PNG |
| A logo with a transparent background | A printer or an office document | PNG, or JPG with the matte set to the final background colour |
| A screenshot of text | Documentation, a bug report | PNG — JPG scatters halos around every character |
| A WebP a colleague cannot open | Older software | JPG for photos, PNG if it has transparency |
How to Read Your Result
Set the matte to the background it will sit on
White is right when the image lands on a white page. If the logo is going onto a dark header, converting with a white matte gives it a white halo that no amount of CSS will remove. Set the matte to the destination colour, or keep a format with transparency.
A PNG that gets bigger is telling you something
If converting to PNG produces a much larger file, the source was photographic and PNG is the wrong destination. If converting to JPG produces a larger file, the source was flat-colour artwork and JPG is the wrong destination. The size comparison in each row is a format-fitness check, not just a statistic.
Convert once, from the best source you have
Every lossy step compounds. Going PNG → JPG → PNG → JPG is four re-encodes and three of them are pure loss. Keep the original and convert from it each time rather than converting the converted file.
Limitations & Accuracy Notes
- Whatever your browser can decode is accepted, so support for newer formats such as AVIF and JPEG XL depends on the browser rather than on this tool.
- Animated GIF and animated WebP are flattened to their first frame. This converts still images.
- Colour profiles are not carried through. A wide-gamut image is treated as sRGB, which can slightly desaturate very saturated colours.
- EXIF and GPS are dropped by the re-encode. Orientation is applied to the pixels first, so nothing comes out sideways.
- PNG output is a browser encode, not an optimiser — expect a dedicated tool such as oxipng to produce a smaller PNG.
Frequently Asked Questions
Which format should I actually use?
Can I convert WebP to JPG or PNG here?
Does converting to PNG improve a JPG?
Why is my converted PNG so much bigger than the JPG?
Are the files uploaded anywhere?
References & Further Reading
- Google — WebP Compression Study
- MDN — Image file type and format guide
- MDN — Common MIME types — The media types the format picker writes
- web.dev — Use WebP images