Deleting unused images

I recently purchase the pro version.
I just got done checking the image tab.
I have about 3500 unused images mostly different thumbnail sizes.
If I delete these, is this gonna trigger Google errors that I will have to fix later.

I hate to get rid of them only to find I have to do lots of work with redirects or something else.

Thanks for any advise on this before I commit to deleting them.

Tom