Procore's own Photos upload guidance names the problem outright: larger file sizes, over 5MB, may time out when uploading, and if you hit a timeout you should reduce the file size — for example by resizing the image in an image editor. On a site connection that advice is the difference between a progress update landing and a foreman tapping retry for twenty minutes. Procore accepts .jpg, .jpeg, .tif, .tiff, .gif, .png, .x-png and .bmp in a photo album, and it notes a wrinkle worth knowing: TIFF uploads succeed but will not display inside Procore, so a TIFF that passes upload is invisible to the reviewer. The practical target is a JPG or PNG under the 5MB mark with enough resolution to read a label on a panel or a crack in a slab. That is a resize plus a moderate quality pass, not a heavy downscale — most 12MP phone photos land well under 5MB at a 1600-2000px long edge with detail intact. Skwish resizes and compresses in the browser, shows before and after per file, and packs the finished set into one ZIP for the drag-and-drop upload.