Images
What is JPEG?
Short for Joint Photographic Experts Group. Also called JPG.
JPEG, often written JPG, is the most widely used photo format. It makes files small by discarding detail the eye is least likely to notice.
How it works
JPEG is named after the committee that created it in 1992. Files typically use .jpg or .jpeg extensions, and nearly every camera, phone, program and website supports it.
It works by dividing the image into small blocks and describing each block’s patterns of light and color, then discarding the fine variation people are least sensitive to. A quality setting controls how much is thrown away. At high quality, the loss is invisible; at low quality, blocks, blur and halos around edges appear.
JPEG vs PNG
| Feature | JPEG | PNG |
|---|---|---|
| Compression | Lossy | Lossless |
| Best for | Photographs | Screenshots, logos, text |
| Transparency | No | Yes |
| Typical photo size | Small | Large |
Choose JPEG for photos that need to be shared or uploaded, and PNG for anything with sharp edges, text or transparency.
A practical example
A camera photo exported as JPEG can be much smaller than a PNG of the same scene, while a logo with fine text may show fuzzy edges and halos.
What to watch out for
Repeated lossy exports can accumulate damage. Keep the original and create each new export from it rather than repeatedly editing a compressed copy.
Tools you can use
- Image Converter · Change an image from one format to another
- Image Compressor · Cut file size with a visible quality trade-off
- Image Resizer · Scale to a size, a percentage or a platform preset
- PDF to JPG · Every page as an image, at the DPI you need
Go a little deeper
- How to convert a PDF to JPG on a phone
- How to reduce image size without losing visible quality
- How to resize an image for a website
- Why do images save as WebP instead of JPG?
Common questions
Is JPG the same as JPEG?
Yes. They are the same format. Early versions of Windows allowed only three-letter extensions, so .jpg became common, and both extensions are accepted everywhere.
Does saving a JPEG again reduce its quality?
Each re-save re-compresses the image and can add a little more loss. Opening and viewing a JPEG doesn’t change it; only saving an edited copy does.
Can a JPEG have a transparent background?
No. JPEG has no alpha channel, so transparent areas are filled with a solid color, usually white or black. Use PNG or WebP for transparency.