JPG vs PNG: what is the difference
Tools Nimbus is a free, no-signup developer toolkit that runs entirely in your browser, so your data is never uploaded to a server. The core difference is compression: JPG is lossy and tiny, best for photographs; PNG is lossless and supports transparency, best for logos, screenshots, and text. Choose JPG for photos and PNG for graphics, then shrink either one locally with the Image Compressor.
Last updated July 2026
The short answer
JPG (also written JPEG) and PNG are both raster image formats, meaning they store a picture as a grid of pixels. The decision between them comes down to two properties: how they compress, and whether they support transparency. JPG uses lossy compression that permanently discards some data to reach very small file sizes, and it has no transparency. PNG uses lossless compression that reconstructs the image perfectly, and it supports an alpha channel for transparent backgrounds. As a rule of thumb: reach for JPG when the image is a photograph and file size matters, and reach for PNG when the image has sharp edges, text, flat color, or needs transparency.
Side by side
| Property | JPG / JPEG | PNG |
|---|---|---|
| Compression | Lossy (discards data) | Lossless (keeps every pixel) |
| Transparency | No | Yes (alpha channel) |
| Best for | Photographs, complex color | Logos, screenshots, text, line art |
| Typical file size | Small for photos | Small for flat graphics, large for photos |
| Colors | 24-bit (16.7M) | Up to 24-bit truecolor, or 8-bit palette |
| Re-saving | Degrades (generation loss) | No quality loss |
| Animation | No | No (APNG is a rare extension) |
| Universal support | Yes | Yes |
What lossy vs lossless actually means
Lossy compression, used by JPG, looks at the image and decides which details the human eye is least likely to miss, then throws them away. It is extremely good at this on photographs, where smooth gradients of color hide small errors, which is why a 4 MB photo can drop to 400 KB with no obvious change. The cost is that the discarded data is gone forever, and pushing the quality slider too low produces visible blocky squares and halos around edges. Lossless compression, used by PNG, never discards anything. It finds patterns and stores them more compactly, so decompressing rebuilds the original pixel for pixel. That guarantee is why PNG is the right choice whenever an image contains crisp text or hard edges that lossy compression would smear.
Why photos are smaller as JPG but graphics are smaller as PNG
It surprises people that neither format is universally smaller. A photograph has millions of subtly different colors, which PNG has to record almost exactly, producing a large file; JPG can approximate those colors and win easily on size. A logo, screenshot, or diagram is the opposite: it has large areas of identical color and only a few distinct tones, which PNG compresses down to almost nothing, while JPG wastes space describing the same flat regions and, worse, adds fuzzy artifacts around the sharp text. So the honest answer to "which is smaller" is: JPG for photos, PNG for flat graphics. Match the format to the content and you get both smaller files and better quality.
Transparency: the deciding factor for logos and UI
If any part of your image needs to be see-through, the choice is made for you: PNG supports an alpha channel and JPG does not. This is why brand logos, app icons, and interface assets that sit on top of other content are almost always PNG. Export the same logo to JPG and every transparent pixel becomes a solid color (usually a white box), which looks broken the moment it lands on a colored background. If you do not need transparency and the image is a photo, that white-box problem never comes up and JPG is fine.
Generation loss: the trap of editing a JPG repeatedly
Because JPG is lossy, every time you open a JPG, edit it, and save again, the format re-compresses and discards a little more detail. Do this dozens of times and a crisp photo slowly turns soft and blocky, an effect called generation loss. PNG has no such problem: you can save it a thousand times and it stays identical. The practical workflow is to keep a lossless master (a PNG or your editor's native file) while you work, and export to JPG only once, at the end, for delivery. If you have two versions of an image and want to confirm whether they actually differ, you can compare their text metadata or Base64 with the Diff Checker.
Where WebP and AVIF fit in
JPG and PNG are not the only options anymore. WebP and AVIF are newer formats that support both lossy and lossless modes plus transparency, and they typically produce smaller files than either JPG or PNG at the same quality. They are now supported in every current major browser, so for a website they are worth considering. The reason JPG and PNG still dominate is universal compatibility: every device, email client, and legacy tool opens them without question. A common strategy is to serve WebP or AVIF where supported and fall back to JPG or PNG everywhere else. For anything that has to just work when you email it or drop it into an old system, JPG and PNG remain the safe default.
How to choose in one line
Use JPG for photographs and any rich-color image where a small file matters and you do not need transparency; use PNG for logos, icons, screenshots, diagrams, and anything with sharp text or a transparent background. Whichever you pick, compress it before you ship it: the Image Compressor shrinks JPG and PNG entirely in your browser with no uploads. If you need to embed a small image directly in HTML or CSS, convert it with the Base64 Encoder and Decoder. For more on cutting image weight without a service, see our guide to a free alternative to TinyPNG, and the full set of tutorials lives on the Tools Nimbus guides index.