There is always a reason a site or program refuses a file: “unsupported format”, a WebP that will not open in a word processor, a logo with a black background after conversion. Understanding what each format does well avoids most of these troubles and lets you choose in a minute instead of by trial and error.
The four formats in one table
| Format | Compression | Transparency | Best for | Compatibility |
|---|---|---|---|---|
| JPG | Lossy (adjustable) | No | Photos | Universal. |
| PNG | Lossless | Yes | Screenshots, logos, diagrams, text | Universal. |
| WebP | Lossy or lossless | Yes | Web page images | All current browsers; some old programs, print services and messaging apps ignore it. |
| SVG | None: vector drawing (shapes described as text) | Yes | Logos, icons, simple illustrations | Browsers; no photos. |
Lossy means saving discards detail to gain space; lossless keeps every pixel. SVG is a case apart: it holds no pixels, but drawing instructions, hence perfect sharpness at any size.
JPG to PNG: useful, but never to slim down
JPG to PNG produces a PNG that keeps the JPG's exact pixels. It is useful for software that accepts only PNG or to avoid adding fresh loss during retouching. Two warnings: PNG does not restore detail the JPG compression had already discarded, and it weighs much more: a photo saved as PNG is often three to eight times heavier than the same JPG.
A quick decision tree
- It is a photo to publish or send: JPG (or WebP for a website).
- It is a screenshot, a diagram, text: PNG.
- You need transparency: PNG (or WebP/SVG).
- It is a logo that must stay sharp at any size: SVG, with a fallback PNG exported at the scale you want.
- The recipient does not understand WebP: JPG.
Common mistakes
- Converting a JPG to PNG to “improve quality”: it only bloats the file.
- Converting a JPG to JPG repeatedly: each save adds loss.
- Sending a WebP to someone whose app cannot open it.
Honest limits
- Conversions are done by your browser: a file over 100 MB or over 100 megapixels is refused.
- Metadata (GPS position, camera model) is not copied into converted images.
- No conversion restores lost detail: always start from the least compressed original.
Frequently asked questions
Is PNG better than JPG?
It is better for screenshots, logos and text, because it loses nothing. For a photo it is much heavier with no visible benefit.
Why won't my WebP open?
Some old programs, print services and messaging apps do not handle it. Convert it to JPG with the dedicated tool.
How do I keep transparency?
Use PNG, WebP or SVG. JPG has none: the transparent area will be filled with a colour.
Can a JPG be converted to SVG?
Not faithfully: an SVG is a vector drawing, not a pixel grid. Only a redraw or an approximate vectorisation produces one.
Are my images sent to a server?
No. Conversions run in your browser.