I recently reworked the naming convention of some images on our website. When I uploaded the images with altered names, I ended up getting the images duplicated, one copy with the old naming convention and one with the new naming convention. The images numbered in the thousands and so I didn't want to manually delete them all.
So I decided that I needed to figure out a php script that would be capable of deleting the old images from the site. Luckily the old images were consistently named with either an ending of f.jpg or s.jpg. So all I had to do is find all the files with those endings and delete them. I thought it was a fairly straightforward thing, but for whatever reason the several different solutions I found listed online didn't work right. I ended up going back to some old code I had posted on Stackoverflow for a different purpose and reworked it for this. I'm posting that code as the answer to my problem in case it might be useful to anyone else.