Sunshine – Unused Image Sizes – Stalls

I am trying to use this tool Unused Image Sizes in Sunshine Photo Cart.
I get a progress bar that’s very slow, it goes fast sometimes, then it slows down for a minute.
It goes to about 1100/1400 and then nothing happens for 30min+
There’s a list of numbers below the progress bar that goes nowhere, nothing listed.
I am not so sure if 1400 is too much, if there’s a problem, if it does anything at all. The only button I have is Abort. I wish I could do it in smaller chunks I don’t know maybe 300 at a time ?
I never got anywhere with this tool.
Can someone point me in the right direction please, I just want to clean the website a bit, make it faster, clean the database of gunk, etc.
I am a pro/paying user.
Thank you!

The page I need help with: [log in to see the link]