My bad, accidently copied over 12,000 photos to desktop

While trying to copy 12,000+ photos onto micro sd card, the photos instead copied to desktop. I have a MacBook Air with Mojave. It has 2 GHz Intel core i7 and 8 GB of 1600 MHz DDR 3 ram. The finder app now is using around 100 percent CPU.

Specifically I can not stop Finder from restarting and using high CPU. If I quit finder it starts right back up. When it does show me a list of photos. I can't interact with the list to try and delete them. I am wondering if there might be a safe mode like in Windows to be able to move all photos to a single folder as now they are all opened individually.

"trying to copy"… from where?

If you hover over the copy Notification, an Ⓧ will float into view.
Click it to stop.

If it was an actual copy, just delete the ones that copied so far. If it was a Move, then hit Cmd/Z to undo. [This is dependent on my opening question.]

BTW, Mac checks the copy will fit before it starts, so if you've had to wait too long & it's now finished, you should still be OK for storage space - just make sure you know whether it was a copy or a move. If you've gone on to do other things after a move, then Cmd/Z won't work; it can only undo the last few things you did, in sequence [max 20 steps].