gallery-dl is a command-line program to download image galleries and collections from several image hosting sites (see Supported Sites). It is a cross-platform tool with many configuration options and powerful filenaming capabilities.

This program tries to recover the lost precision of DCT coefficients based on a quantization table from a JPEG image. The result is saved as a JPEG image with quantization set to 1 (like a JPEG saved at 100% quality).

You may not notice jpeg artifacts on the screen without zooming in, but you may notice them after printing. Also, when editing compressed images, artifacts can accumulate, but if you use this program before editing - the result will be better.