Most people pick an image format by accident — whatever the camera or the download button gave them. That's fine until a logo turns out to have an ugly grey box behind it, or a simple graphic somehow weighs 4 MB.
There are really only three formats worth knowing for everyday use, and each one is good at a different job.
The one-line summary
| Format | Use it for | Transparency |
|---|---|---|
| JPG | Photographs | No |
| PNG | Logos, graphics, screenshots of text | Yes |
| WebP | Anything going on a website | Yes |
If you remember nothing else, that table covers 95% of real situations. But the reasons behind it are worth understanding, because they explain the odd results you sometimes get.
JPG: built for photographs
JPG uses lossy compression. It permanently throws away information that human eyes are bad at noticing — mostly fine colour variation — and keeps the brightness detail we're sensitive to. On a photo of a face, a landscape or a meal, this works remarkably well. You can often cut a file to a tenth of its size before anyone notices.
Where JPG falls apart
The same trick that works on photographs fails badly on sharp-edged graphics. Around hard lines — text, logos, thin borders — JPG produces faint smudges and halos called artifacts. Screenshot a page of text, save it as JPG, and the letters develop a fuzzy grey aura.
JPG also cannot store transparency. Save a logo with a transparent background as JPG and the transparent area becomes solid white — which is exactly why so many logos end up sitting in a white rectangle on a coloured page.
Every save costs you. JPG re-compresses each time you save. Open a JPG, crop it, save, repeat a few times and the quality visibly drops. Always edit from the original where you can, rather than repeatedly re-saving the same JPG.
PNG: built for graphics and transparency
PNG uses lossless compression. Nothing is discarded — the file you open is pixel-for-pixel what you saved. It handles hard edges perfectly, so text stays crisp and logos stay clean.
It also supports a full alpha channel, meaning each pixel can be fully opaque, fully transparent, or anything in between. That's what allows a cut-out to sit naturally on any background, with soft edges around hair rather than a hard jagged outline.
Where PNG falls apart
File size. On a photograph, lossless compression has very little repetition to exploit, so a PNG photo is often five to ten times larger than the same photo as JPG, with no visible benefit. Saving holiday photos as PNG is one of the most common ways people accidentally fill up their storage.
Rule of thumb: if the image has a few flat colours and sharp edges, PNG is excellent. If it has thousands of subtly varying colours, PNG is the wrong tool.
WebP: the modern compromise
WebP was designed for the web specifically, and it can work either way — lossy like JPG or lossless like PNG — while supporting transparency in both modes.
In practice it produces files roughly 25–35% smaller than JPG at similar visual quality, and considerably smaller than PNG for graphics with transparency. Every current browser supports it.
Where WebP falls apart
Compatibility outside the browser. Some older desktop software, printing services, and government or bank upload portals still only accept JPG or PNG. WebP is the best choice for your own website; it is a risky choice for a file you need to hand to someone else.
Choosing in practice
A photo for social media or messaging
JPG, quality around 80%. Universally supported, small, and social platforms will re-compress it anyway.
A logo, icon or anything with transparency
PNG if it's going anywhere outside a website. WebP if it's for your own site and you want it lighter.
An image for your website
WebP. It's the reason many sites load noticeably faster than they used to.
A document scan or screenshot with text
PNG. The text stays readable. JPG will blur exactly the fine detail that matters.
An upload to a government portal, bank or job site
JPG, unless the instructions say otherwise. It's the safest format for systems you can't test in advance.
A few common mistakes
- Converting JPG to PNG to "improve quality." It doesn't. The detail JPG discarded is gone; PNG just wraps the damaged image in a bigger file.
- Using PNG for photos because "lossless sounds better." Correct in theory, wasteful in practice — you get a much larger file for a difference nobody can see.
- Assuming the extension defines the format. Renaming
photo.pngtophoto.jpgchanges nothing about the data inside. To genuinely change format you have to re-encode it.
Converting between them
You can convert between all three in your browser without installing anything. Open the compressor, load your image, choose the format you want from the dropdown, and download:
Open the PIXNIVO compressor →One thing worth remembering when converting: going from JPG never restores quality. If you have a choice, always start from the highest-quality original you have rather than from a file that's already been compressed.