Delete photos from Mac?

I hope someone can help me.

I took over his Mac from my husband because my laptop is broken. I have zero experience with Apple. Now I sat on the PC for two hours to upload my photos and videos from my Huawai cell phone to my Mac. Somehow he pulled everything three times, from the cell phone and from my Dropbox. I now have 3,500 files instead of 1,000 files. How can I undo this?

You have no choice but to mark all files that you want to delete and then delete them. Are the files all mixed in one folder? Then they have different names, then you could work with the search function.

There are 3 ways to delete files in macOS:

Drag and drop files into the trash
Right click> "Put in trash"
Shortcut: cmd + Enter

Can you maybe send a screenshot of what it looks like now? Then maybe I can help further.

Your Dropbox data is not on your PC but I believe that the files are linked to the Dropbox. You could delete everything, just move it to the trash as normal. Then choose your source carefully and the type where you get your data from. Pay attention to loading processes, whether something starts automatically. Basically, all pictures should be in the DCIM folder, just copy this if nothing else happens after connecting to the PC.

A kind of activated backup on the mobile phone would also be possible, which includes all sources where pictures are and makes a backup when an external source is plugged in.

No, normally the data of the Dropbox is completely mirrored on the Mac.

If they are deleted from there, they also disappear from Dropbox via synchronization.

Before you pounce more or less headless on the photos, read https://support.apple.com/...new-to-mac in peace.

The excess pictures wait so long and don't break anything.

Then look for the Photo Duplicate Cleaner app in the App Store and download it. It will help.

Hm okay, that both then disappear, that they are on the mac was new to me.