What is JPEG?
JPEG (Joint Photographic Experts Group) is a lossy raster image format that uses discrete cosine transform compression to shrink file size by discarding image detail humans are less likely to notice. It has no alpha transparency, so it is best for photographs and gradients rather than logos, icons, or text.
Example
A photo can typically be compressed to 5-10% of its raw size with minimal visible quality loss.
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