Range split to keep sections intact; per-page split for uploads.
Formats like 1-3,5,8-10 work; page numbers start at 1, not 0.
Range split returns one file, per-page split returns a zip.
Splitting by page range suits cutting a book into chapters or pulling a few pages out of a bundle. Splitting every page into its own file suits tender portals that only accept single pages, or scans that must be filed per person. The first gives you a handful of files; the second can give you a hundred.
If single-page upload is the goal, check the naming convention. Most tools name files by page number, but some portals require the file name to be just the number — get it wrong and you upload them all again.
Cut a 40MB file in half and you get two 20MB files with zero quality loss. When the only constraint is file size, splitting is always better than lossy compression. Only when page count is also capped do you need to compress first.
Links pointing to pages that were split away stop working — that is unavoidable.
Yes, run it twice with different ranges.
No, splitting happens locally in the browser.