JPG and PNG are the two most common image formats on the web. Both look fine on screen, but they work in completely different ways under the hood. Pick the wrong one and your photo can look blurry, or a simple logo can end up needlessly heavy.
The short version: JPG suits images with smooth, continuous color like photographs, while PNG suits images that need crisp edges and transparency like logos, text, and icons. Here is why.
Lossy vs lossless compression
The biggest difference is how each format compresses data. JPG uses lossy compression: it throws away detail your eye is unlikely to notice in exchange for a much smaller file. In a landscape photo where colors shift gradually, that loss is nearly invisible, which makes JPG extremely efficient.
PNG uses lossless compression. It shrinks the file without discarding a single original pixel. As a result, a PNG is usually heavier than the same image as a JPG, but it suffers no quality loss at all.
Do you need a transparent background?
PNG supports transparency (an alpha channel). If you need a logo that shows the background through it, a cut-out subject, or icons you layer over other elements, you need PNG. JPG has no transparency, so any transparent area gets filled in with white or black.
On the other hand, if your photo has no transparent areas at all, PNG offers no advantage and only makes the file larger.
Measured: which format is lighter for which image
The format debate has no answer without naming the kind of image. We encoded three sources of different character under identical conditions and read the actual file sizes.
| Source type | JPG quality 80 | PNG (lossless) | Lighter |
|---|---|---|---|
| Photograph (smooth gradients) | 269 KB | 3,591 KB | JPG — PNG is 13.3x heavier |
| Flat graphic (solid areas) | 29 KB | 23 KB | PNG — 20% lighter than JPG |
| Screenshot (small text) | 97 KB | 94 KB | About equal — PNG wins on quality |
JPG dominates on photographs, but for graphics built from few colors and large flat areas PNG is actually lighter. That is why the folk wisdom that PNG is heavy is only half true. Screenshots come out about the same size, and since PNG looks better there, PNG is the right pick.
More visible than the file size is what happens to text. Below is the same region of one screenshot enlarged four times: PNG on the left, JPG quality 40 on the right.
File size and repeated saving
File size matters for page load speed and uploads. Keep these tendencies in mind.
- Photos = JPG is far lighter at the same visual quality
- Logos, charts, screenshots = PNG keeps text edges sharp
- JPG loses a little quality every time you re-save it (generation loss); PNG stays identical no matter how many times you save
Recommendations by situation
Here is the simple rule. Use JPG for camera and phone photos, images with a full background, and pictures you send casually by email or chat. Use PNG for transparent logos, graphics where text must stay crisp, screen captures, and master files you keep before printing.
If a file you already have is in the wrong format, just convert it. You can turn a PNG logo into a JPG to save space, or a JPG photo into a PNG to avoid loss during editing. With Switching, files are processed entirely inside your browser and never uploaded to a server, so even personal photos stay private.