There are dozens of image formats, but you only meet a handful in daily life. Here is a quick, practical tour of each — what it is good for, and where to convert it when you need something else.
We measured this ourselves. The clearest illustration of what compression actually means came from our BMP tests: all three BMP source files are byte-for-byte 2.75 MB, whether they contain a grainy photo or six flat colours. BMP stores every pixel raw, so the file size does not depend on the picture at all. Convert the same pixels to PNG — lossless, identical image — and the flat ones drop by 99%. see the full measurements
Raster formats (made of pixels)
- JPG / JPEG — lossy, small, no transparency. The default for photos. (You may also see JFIF, which is literally the same thing with a different extension.)
- PNG — lossless with transparency. Best for logos, icons and screenshots. See PNG vs JPG for the full comparison.
- WebP — a modern format that is smaller than both, with transparency. Great for websites — details in What is WebP.
- AVIF — the newest and often smallest, based on the AV1 codec, but not yet openable everywhere. See What is AVIF.
- GIF — limited to 256 colors, known for animation. For a static frame, convert GIF to PNG.
- BMP — an old, uncompressed Windows format; files are huge. Shrink one with BMP to PNG.
The difference between these raster formats is easiest to see on one image. Our flat illustration is 10.8 KB as WebP; the same picture is 23.7 KB as JPG (+119%) and 94.0 KB as PNG (+769%). Nothing about the picture changed — only how the format chooses to store it.
Vector format (made of math)
- SVG — shapes described by mathematical paths, so it scales to any size without blur and stays tiny. Perfect for logos and icons. You can even turn a PNG into an SVG by tracing it.
For documents
- PDF — not an image format, but where images often end up. You can combine images into a PDF or pull pages back out as images.
Which should I use?
- A photo? → JPG (or WebP/AVIF for the web).
- A logo, icon or screenshot? → PNG (or SVG if it is a simple graphic).
- A fast website? → WebP or AVIF, with a JPG/PNG fallback.
- A file too big to send? → compress it.
And the choice is not reversible for free. Starting from a 25.6 KB JPG of that illustration, converting to PNG gave 143.8 KB (+461%): PNG faithfully stores the JPEG artefacts as if they were detail. Pick the format for where the file is going, not for where it came from.
Convert between any of them
Every conversion runs in your browser — nothing is uploaded. Browse the full set on the image converters hub, or jump straight to a common one like PNG to JPG, PNG to WebP or compress an image.
Once you know what each format is for, choosing — and converting — takes seconds.
Lossy vs. lossless: the other big divide
Beyond raster and vector, formats also split by how they store data:
- Lossy (JPG, and by default WebP and AVIF) throws away detail the eye barely notices to shrink the file. Great for photos — but re-saving the same file repeatedly slowly degrades it.
- Lossless (PNG, GIF, BMP, and the lossless modes of WebP and AVIF) keeps every pixel exactly. Essential for logos, text, screenshots and anything you will edit again.
The lossy/lossless divide is easiest to see going the wrong way. Converting a JPG to PNG cannot recover anything — and it costs:
| Test image | Input | Output | Change |
|---|---|---|---|
| Screenshot | 45.2 KB | 72.8 KB | +61% |
| Photo | 330.2 KB | 2.07 MB | +542% |
Our screenshot as JPG was 45.2 KB; as PNG it became 72.8 KB (+61%). PNG is lossless, so it faithfully stored the JPEG’s compression artefacts as if they were detail — every ringing edge and blocking square preserved forever, at several times the size. Lossless does not mean “good quality”; it means “exactly what you gave it”.
Two more you may meet
- HEIC — the format iPhones use for photos. Efficient, but not web-native; see how to convert HEIC to JPG.
- TIFF — a high-quality, often uncompressed format used in printing and archiving. Details in what is TIFF.
Quick reference
| You have or want | Best format |
|---|---|
| A photo to keep or share | JPG |
| A photo on a fast website | WebP or AVIF |
| A logo, icon or screenshot | PNG |
| A scalable logo or icon | SVG |
| A short animation | WebP (or GIF for maximum compatibility) |
| A print-ready master | TIFF or high-quality PNG |
FAQ
What is the difference between raster and vector?
Raster images are a fixed grid of pixels and blur when enlarged. Vector images are described by math, so they scale to any size and stay sharp — but they only suit flat graphics, not photos.
Which format gives the smallest file?
For photos, AVIF is usually smallest, then WebP, then JPG. For flat graphics, SVG or lossless WebP often wins.
Can I turn a photo into an SVG?
Not usefully. SVG suits logos and line art; tracing a detailed photo produces a huge, messy file. Keep photos as JPG, WebP or AVIF instead.