A manuscript with figures is a folder problem, not a single-file problem. A 200-page non-fiction book can carry 80 images, and KDP's 650 MB manuscript cap is reached one plate at a time rather than dramatically. Doing that by hand means opening each file, guessing a quality level, and losing track of which ones were touched. A batch pass fixes the repetitive half: drop the folder, pick one output format and one size target, and get every image back at a predictable weight with before and after listed per file. Two rules still need a human decision per image. First, DPI at display size is what KDP checks, so a table screenshot and a full-page plate cannot share the same pixel target. Second, anything with transparency should stay PNG while photographic plates can go to JPEG, because flattening a transparent figure onto white is a silent quality loss. Skwish processes the batch in the browser, keeps formats straight, and hands the set back as a single ZIP.