Moodle is the one platform where asking what the upload limit is has no single answer. MoodleDocs describes a cascade: the web server's LimitRequestBody, then PHP's post_max_size and upload_max_filesize, then the site-wide Maximum uploaded file size under Site administration, then course default settings, then the individual course, then the assignment activity's own file size setting. The documentation is explicit that the order cannot be inverted — a course setting cannot override the site setting, the site setting cannot override php.ini, and php.ini cannot override the server. In practice that means an assignment can refuse a 30MB file on one Moodle site and accept a 200MB file on another, and a teacher who believes they raised the limit may have raised only the layer they can reach. What Moodle is permissive about is type: the assignment activity accepts uploaded files of any type the teacher's device can read, so the format is rarely the problem and size always is. The other practical detail is that Moodle sits in front of Turnitin in many institutions, and Turnitin independently caps submissions at 100MB, under 800 pages, with at least 20 words of readable text — so a photo-only submission can pass the Moodle limit and still fail the originality check. Compressing and resizing before upload clears every layer of the cascade at once. Skwish runs in the browser, resizes to a fixed long edge, compresses to a target size and ZIPs the set.