The short version: use JPG for photographs and PNG for anything with text, sharp edges, or transparency. A photo saved as PNG is typically 5–10× larger than the same photo as JPG with no visible benefit — and a screenshot saved as JPG picks up smeary artefacts around every letter. Below is the full comparison, the size numbers, and free PNG to JPG and JPG to PNG converters that run entirely in your browser.
PNG vs JPG at a glance
| PNG | JPG (JPEG) | |
|---|---|---|
| Compression | Lossless | Lossy |
| Transparency | Yes (alpha channel) | No |
| Best for | Screenshots, logos, text, line art, UI | Photographs, camera output |
| Typical photo size (1920×1080) | ~2.5 MB | ~300 KB |
| Typical screenshot size (1920×1080) | ~180 KB | ~250 KB |
| Colours | 16.7M + alpha | 16.7M |
| Re-saving repeatedly | No quality loss | Degrades every save |
| Animation | No (APNG is separate) | No |
| Browser support | Universal | Universal |
Note the size rows are the opposite way round depending on content — that is the whole decision in one table.
Why a photo is smaller as JPG
JPG throws information away. It works in 8×8 pixel blocks and discards the high-frequency detail your eye is worst at noticing, which is why a photograph compresses so dramatically with no obvious change. On a 1920×1080 photo that is often the difference between 2.5 MB and 300 KB.
PNG never throws anything away. It compresses by finding repeated patterns, which works brilliantly on flat colour and terribly on the noisy, never-repeating pixel values that make up a real photograph.
Why a screenshot is smaller as PNG
Flip the content and the logic flips with it. A screenshot is mostly large areas of identical colour with hard black-on-white edges — exactly the pattern PNG compresses well and exactly the pattern JPG handles worst. JPG's block-based compression produces visible "ringing" around text, which is why screenshots saved as JPG look faintly dirty around every letter.
The transparency question
Only PNG has an alpha channel. If any part of your image needs to be see-through — a logo over a coloured background, an icon, a UI element — it must be PNG (or WebP, or SVG). Converting a transparent PNG to JPG does not fail; it silently fills the transparent area with a solid colour, usually white or black. That is the single most common surprise when converting.
Quick decision guide
| Your image is… | Use |
|---|---|
| A photo from a camera or phone | JPG |
| A screenshot | PNG |
| A logo or icon | PNG (or SVG) |
| A graphic with transparency | PNG |
| A photo for a website, size matters | JPG (or WebP) |
| An image you will edit and re-save repeatedly | PNG |
| Scanned text or a diagram | PNG |
What about WebP?
WebP is the modern answer to both. It does lossy compression like JPG, lossless compression and transparency like PNG, and typically lands 25–35% smaller than JPG at matched quality. Browser support is universal now, so for images on a website WebP is usually the better choice — the main reason to stay on PNG or JPG is compatibility with older software and printers.
You can convert to it with the free JPG to WebP converter, or back out with WebP to PNG and WebP to JPG.
Converting between them
Every converter linked here runs entirely inside your browser using the browser's own image engine. Your images are never uploaded, never stored on a server, and there is no signup, watermark, or size wall.
One thing to know before converting: going from JPG to PNG does not restore quality. The detail JPG discarded is gone permanently, and the PNG simply stores the already-degraded image losslessly — at a much larger file size. Converting JPG → PNG is worth doing when you need transparency or lossless editing from that point on, not to "improve" an existing JPG.
- PNG to JPG — shrink screenshots-turned-photos
- JPG to PNG — when you need a lossless master
- Resize an image — often a bigger win than either conversion