You need to find an image hosting site such as: photobucket. Just google "free image hosting". Pick one that you like. Some you have to register (free) and some you don't.
Anyway, after you upload your pictures to that site, you will then get a choice of URL's. Choose one by copying it to the clipboard (using Cntrl C). Then come back to this site and paste (using Cntrl V )the URL here. - paste everything in between