Lossless compression is preferred for archival purposes and often for medical imaging, technical drawings, clip art, or comics.
Image compression may be lossy or lossless.
Lossless compression is used in cases where it is important that the original and the decompressed data be identical, or where deviations from the original data would be unfavorable. By contrast, lossy compression permits reconstruction only of an approximation of the original data, though usually with greatly improved compression rates (and therefore reduced media sizes). Lossless compression is a class of data compression algorithms that allows the original data to be perfectly reconstructed from the compressed data.
