Q: Storage not updating after deleting files

My 500GB iMac hard drive is running out of storage space. These days we are using the computer mainly for photo and movie editing, so I manually backup my photos and any other important files to an external hard drive (to be clear, I DO NOT use Time Machine). To clear up space, I decided to delete the majority of duplicate photos in the many years of albums in the Photos app and was planning on doing the same in iMovie and iDVD afterwards. I deleted the extraneous photos from Photos and then deleted the files from the "Recently Deleted" folder in Photos, then emptied the trash, which took about 30 minutes. I then restarted the computer.  I previously had about 106GB of photos on the internal hard drive, and I estimate that I deleted a good 80% of these. However, upon restarting the computer and checking my storage, the overall storage and photo storage amounts had remained the same. What's going on?