You’ve become aware that copying photos and graphic images you find on the internet might be considered stealing them. This may or may not be morally wrong but breaking the law is at least a bit problematic. If you need pictures and don’t want to pay for them, here are sources for getting them legally free:
Images licensed under Creative Commons terms are free to use although they do have some strings attached to them (creators want to be named, for one thing). Photopin is a repository where you can find plenty of “free” Creative Commons pictures.