JPG vs PNG: When Each Format Wins
JPG and PNG are the two formats almost everyone ends up choosing between, and the advice you usually get ("JPG for photos, PNG for graphics") is correct but unhelpfully thin. This page explains why that rule exists, what each format is actually doing to your pixels, and how to tell which one a particular image wants. When you have decided, the free image converter switches between them on your own device.
Short answer: photographs and anything with soft gradients belong in JPG. Text, screenshots, logos, line art, and anything needing a transparent background belong in PNG. If both sound plausible, try both and compare the file sizes; the format that wins usually wins by a lot.
The core difference in one paragraph
PNG compresses without changing the image. It looks for runs of identical pixels and repeating patterns, packs them more efficiently, and hands you back exactly what you gave it. JPG compresses by changing the image: it breaks the picture into small blocks, keeps the coarse shapes your eye notices, and throws away the fine variations it assumes you will not miss. That single difference explains every practical trade-off between them, including size, sharpness, transparency, and what happens when you re-save.
Side by side
| JPG | PNG | |
|---|---|---|
| Compression | Lossy, adjustable | Lossless, fixed |
| Transparency | Not supported | Full alpha channel |
| Photographs | Small files, excellent | Very large files |
| Text and sharp edges | Can smear and ring | Perfectly crisp |
| Flat color areas | Can show blocking | Compresses extremely well |
| Re-saving | Degrades a little each time | Never degrades |
| Animation | No | No (APNG is a separate variant) |
| Support | Universal | Universal |
Where JPG wins
Photographs are made of continuous tone. A blue sky is thousands of slightly different blues, skin is a smooth range of warm values, and foliage is visual noise. PNG has to record every one of those tiny differences faithfully, which gives its pattern-matching almost nothing to work with. JPG throws away the differences too small to notice and keeps the structure that matters, which is why the same holiday photo can be several megabytes as a PNG and a few hundred kilobytes as a JPG that looks identical at normal viewing size.
JPG also wins whenever the destination cares about size: email attachments, upload forms with a size cap, listing photos, and anything you are sending over a phone connection. And because JPG has been universal for decades, it is the safest format to hand to someone whose software you do not control.
The quality control matters here. At a high setting, such as the 90% this converter uses by default, JPG artifacts are essentially invisible in normal photographs. Push the slider down toward 50% and the same photo gets dramatically smaller while the damage becomes visible in skies, shadows, and around hard edges. There is no single correct number; there is only the lowest setting where you cannot see the difference on the screen where the image will be used.
Where PNG wins
PNG wins whenever the image contains hard edges between flat colors: interface screenshots, charts, diagrams, logos, icons, comic-style artwork, and any picture that is mostly text. Two things happen at once. First, PNG compresses flat regions brilliantly, because a row of two hundred identical pixels is cheap to describe. Second, PNG keeps edges exactly where they are, so a one-pixel border stays a one-pixel border and small text stays legible.
PNG also wins whenever you need transparency. It is the only one of the two formats with an alpha channel, so a logo that has to sit on any background color has to be a PNG (or a modern format like WebP or AVIF). Our PNG transparency guide covers how alpha channels behave and how to avoid losing them.
Finally, PNG wins as a working format. If you are going to open, edit, and re-save an image several times, doing that in PNG means the tenth save looks exactly like the first.
What JPG artifacts actually look like
Knowing the failure modes makes the choice easy, because you can recognize a bad fit on sight.
Ringing around edges
Look closely at black text on a white background inside a low-quality JPG and you will see a faint halo of grey speckle hugging every letter. JPG works in blocks and describes each block as a combination of smooth waves; a hard black-to-white transition needs a great many of those waves to reproduce, and when the encoder discards the fine ones, the leftover ripple shows up as a shadow around the edge. This is the single biggest reason not to save screenshots of text as JPG.
Blocking in flat areas
In smooth gradients like a clear sky or a studio backdrop, aggressive JPG settings make the block grid visible as faint squares or stair-stepped bands. Because the eye is very good at spotting straight edges where none should exist, this is often the first artifact people notice.
Color bleeding
Most JPEG encoders store color information at a lower resolution than brightness information, on the reasonable theory that human vision is far more sensitive to light and dark than to hue. The side effect is that saturated colored edges, red text especially, can look smeared or fringed while the same text in black stays sharp.
Generation loss
None of these artifacts disappear on the next save. Open a JPG, crop it, save it, then repeat that a dozen times and the accumulated damage becomes obvious. PNG has no equivalent problem: it is bit-for-bit identical every time.
Transparency: the decision that makes itself
If any part of your image must show whatever is behind it, JPG is off the table. There is no quality setting, no encoder trick, and no workaround; the format simply has no place to store the information. When you convert a transparent PNG to JPG with this tool, the transparent areas are filled with white before encoding, because leaving them undefined would render them black in most software. That is often exactly what you want for a photo on a white page, and exactly wrong for a logo destined for a dark header.
The reverse conversion cannot invent transparency either. Turning a JPG into a PNG gives you a lossless container around an opaque picture; the background is still there, it is just now stored perfectly. Removing a background is an editing job, not a conversion job.
A quick way to decide
- Does it need a transparent background? PNG.
- Is it mostly text, or a screenshot of an interface? PNG.
- Is it a photograph, or a photographic crop? JPG.
- Will you edit and re-save it repeatedly? PNG while you work, JPG when you publish.
- Is it going on a website and you control the markup? Consider WebP instead of either.
- Still unsure? Export both and look at the sizes. For a photo, JPG usually wins by a factor of five or more; for a flat-color graphic, PNG frequently wins outright.
Converting between them
Both directions take a few seconds and run entirely on your device: no upload, no account. Use PNG to JPG when a file is too big for an upload limit or an email, and JPG to PNG when a system insists on PNG or you are about to start editing. The quality slider appears only for lossy targets, since PNG has nothing to trade away.
Common questions
Is PNG better quality than JPG?
PNG is lossless, so it stores exactly the pixels it was given, while JPG discards some detail to save space. That makes PNG the more faithful container, but it does not make an existing image look better. Converting a JPG to PNG preserves the JPG's current appearance; it cannot bring back detail the JPG already threw away.
Why is my PNG so much bigger than the JPG?
PNG compression looks for repeated patterns and identical neighboring pixels. Photographs have almost none of that, since every pixel differs slightly from the one beside it, so PNG has little to compress and the file stays large. JPG instead simplifies the image itself, which is why a photo saved as JPG is often a fraction of the PNG size.
Which format should I use for screenshots?
PNG is usually the better choice for screenshots of text, menus, code, or spreadsheets, because it keeps letterforms crisp and compresses flat interface colors well. Screenshots that are mostly photographic content, such as a captured video frame, behave like photographs and are usually smaller as JPG.
Does saving a JPG over and over degrade it?
Yes. Each save re-applies lossy compression to an image that has already been compressed, so small errors accumulate. This is called generation loss. Editing from an original PNG, or keeping an untouched master copy, avoids it. Simply opening and viewing a JPG does not harm it; only re-saving does.
Can a JPG have a transparent background?
No. The JPG format has no alpha channel, so transparency cannot be stored in it at all. When this converter writes a JPG it fills any transparent area with white first, which prevents those areas from turning black. If you need transparency, keep the image as PNG or use WebP or AVIF.
Ready to convert? Drop your image into the free image converter, pick JPG or PNG, and download. Everything happens on your device.