A deck's images arrive as a folder, not one at a time: exports from a camera, screenshots from a phone, charts saved out of a spreadsheet, product shots pulled from a DAM. Compressing them individually means opening each file, guessing a quality level and losing track of which ones you already touched. A batch pass collapses that into one decision. Set one output format and one byte target, drop the folder in, and every image comes back at a predictable weight with the before and after listed per file. Two things still need your judgement. Format: screenshots and charts with text should stay PNG, photographs should be JPEG, and flattening a transparent cutout onto white is a silent quality loss. Frame: if the deck is 16:9, resizing everything toward 1920 x 1080 px is what turns a 90 MB folder into a 9 MB one. Skwish processes the batch in the browser, keeps formats straight and hands the set back as a single ZIP.