Re: Adding One's Own Captions to Clip Art?
Clip-art is just like other artwork - it could be free, it could be licensed. You would have to know the source and find out what the licensing terms are. You say "clip art from social media" but I'm not quite sure what that means. Even images posted on social media belong to someone, unless it explicitly says otherwise.
It would also depend what you want to caption. Is it something funny, creating a parody? Is it changing it to a commercial use? (anything that would work to bring traffic to your business) Some clip-art may come with the right to use it for personal non-commercial use for free.