Repository size is cumulative in a way that single-file limits hide. GitHub's specific limits are clear — 25 MiB per file through the browser, up to 100 MiB through the command line, a warning from git once a file passes 50 MiB, and a hard block above 100 MiB that forces Git LFS or a history rewrite — but the guidance underneath them is the part that matters: GitHub recommends repositories stay under 1 GB, and strongly recommends under 5 GB, because clone time is the cost every contributor pays. Screenshots and design exports are usually the reason a repo drifts upward, since they arrive a few hundred KB at a time and are never deleted from history. The productive order is to compress before the first commit rather than after, and when the weight is already in history, to compress the files that are still referenced and treat the old blobs as sunk cost unless you are prepared to rewrite. Skwish compresses PNG, JPG and WebP in the browser with a per-file before/after readout and a batch queue, so you can measure the whole image directory in one pass instead of guessing from `du` output. Nothing is uploaded.