Steemit is not like facebook, on facebook many people plagiarise and post others people’s work without even thinking about copyright.

This type of activity is frowned upon on steemit. Think about this for a minute, u are posibly going to recieve revenue for your post. If you are trying to gain revenue from someone else’s work and pass it off as your own then voters are probably going to downvote you.

Also if you are downvoted by someone who has a lot of steem power you may end up losing reputation score.
some users accounts have been made unusable by being downvoted so much. so plagiarisers beware.

Its acceptable to use ‘royalty free’ or ‘labeled for re-use’ images for your articles and there also the ‘fair use’ option,but you should quote the source of your txt or image.
If you were to just use someone elses image, without txt or referenc and posted it in the ‘photography’ tag, you would be giving the impression that the image is yours. You could get downvoted.

 If you are going to post good honest original content you will probably do well on steemit.
Also if you can promote steemit or contribute to the steemit community in a positive way then people will probably upvote you.

Your first post on steemit should be your introduction post. This helps other users to see that you are infact a real human and not a bot.

You should take a picture of yourself holding a piece of paper, the paper should show the word steemit and your user name and date.
Most users who follow this precedure gain more attention and then potentially more revenue.