I saved someones pictures from dropbox on my Mac. I dont have permission for them so they're locked?

Go to www.howtogeek.com/ and use the search function to find some information on how to operate your computer. It is very strange that you were able to save something that you are unable to delete.

I have never owned any Apple equipment because the brand has always had a reputation for assuming that you don't own the computer just because you paid for it. IMO that is a breach of contract.