When you upload photos multiple times, the computer can start numbering the photos. IMG_A becomes IMG_A 1 and IMG_A 2 and IMG_A 3.
Using a wildcard * and specifying the ending space and number will help you select the files. For example:
Find all the files that end in "space"1.JPG
find -name '* 1.JPG'
* Have a look at the returned files to make sure you want to delete these
Find AND DELETE all the files that end in "space"1.JPG
find -name '* 1.JPG' -delete
