What you should know
JPEG, standardised in 1992, is the most widespread photographic format in the world. Its lossy compression exploits the limits of the human eye: it keeps brightness precisely and greatly reduces colour data.
Every camera, phone and scanner produces JPEG. It is also the format print services and websites expect by default.
Strengths
- Greatly reduced size for photographs
- Read universally, from cameras to browsers
- Adjustable quality from preview to print
- Handles EXIF metadata: date, device, GPS coordinates
Limitations to know
- Lossy compression: every save degrades the image a little more
- No transparency: JPEG cannot store an alpha channel
- Visible artefacts around text and sharp edges
- Unsuitable for graphics, logos and screenshots
When to use it
JPEG is the right choice for any photograph meant for the web, sending or printing. For a logo, icon or graphic, prefer PNG or WebP: flat areas and lines stay clean there.
Quality, size and compatibility
A quality of 85% suits most web uses; 90–95% for print. Avoid saving a JPEG repeatedly: re-encode from the original, or from a PNG if you need to retouch it.
Frequently asked questions
- How many times can I re-save a JPEG?
- As few as possible. Each save adds a generation of loss, most visible in dark areas and gradients. Keep a PNG copy or the original file for edits.
- Why are my phone photos smaller than my camera's?
- Phones often apply stronger compression to save storage. The displayed size therefore depends as much on the device setting as on the format.