well, usually if you are taking pictures from another site, someone will have the rights on the picture, content.

so if you dont want to be sued, you have to put a link reference to each picture at the bottom of your post, just to be safe.

read this post:
https://steemit.com/stock/@knozaki2015/how-to-earn-money-with-your-precious-pictures-photographer-dont-miss-this

there is a company i found, which is sueing people if you use pictures which do not belong to you.!!!