It totally depends under what license you acquired the picture. Stock agencies tend to sell their images under different licenses. You choose the license depending on what you want to do with the picture.
The standard license for stock images is a Royalty Free license. This license allows you to use the picture for non-commercial, personal purposes only.
If you want to be using photos for commercial purposes, you’ll need to purchase an Extended Royalty Free license. This license allows you to use the picture for sale and redistribution.
Simply put, if you want to make money with the picture, you need to go for an Extended Royalty Free license.
But watch out. Many of the pictures available from stock agencies are sold under an Editorial License. Editorial licensed photos must not be used for commercial purposes.
Such photos usually depict celebrities, public figures, products, trademarks or buildings. Public and copyright laws prohibit the commercial use of such items. You can only use them for editorial purposes, meaning for newspaper or magazine articles, news-related blog posts, non-fiction books, documentaries, and the like.