I need to organise my photos. The way my camera app works is that it just uses the next available number (e.g. photo0001 photo0002 photo0003, etc) and just remembers the next number to use. The issue with this is when you go back and delete photos, it leaves a blank "slot" (e.g. photo0008 photo0010 photo0011 photo0015, photos 9, 12, 13, and 14 were deleted), and if you ever reset your phone, the camera forgets and starts over from 0001, sees that number is already taken, and uses the next available number. This results in your photos being in the correct order if you go by date taken, but a complete mess up you go by filename. I plan to fix this by using a mass-renamer that will rename them in order of date taken. Issue with that is, I have no idea how Google Photos will handle this. It's suddenly going to see thousands of photos that are different from the version stored online (because their filenames now are different) and bundled of new photos which didn't exist before because they are existing photos that had their filename changed to one that wasn't in use before. Will Google Photos be able to tell by performing some sort of visual check or using some sort of hash/checksum? Or is it just going to turn my album into a mess? What would be the best way to deal with this? I could turn off photo syncing, delete everything saved online, then re-enable it after I rename them, but that would mean I would have to re-upload all my photos and videos, my 64gb card is almost full and I am upgrading to 128, that would be a LOT of data to re-upload.