Step 4: Attribute Nothing (and make sure nobody else does either)
Pictures are very similar. When stealing pictures, make sure they don't somehow identify the author. If the author is in the picture or otherwise identified, you need to take action. I suggest cropping the identifying portion out of the picture if possible. This doesn't take much work and is an acceptable picture edit, as discussed in the last step. There are other things you could do, but if it's going to be much work, simply steal a different picture. The easy path is the one that pays dividends now, whether it's "right" is for other people to worry about.
Finally, you need to watch your comments in case somebody recognizes that the project is not yours, or even worse that it is theirs. You should immediately flag these comments, and if that fails, you might try threatening the poster's well-being. I'm quite certain a court of law would side with you and allow you to threaten people when they find out the truth.* It's really just up to you to convince them that you're really the one being threatened, as well as being a victim of intellectual property theft.
*This will also be addressed in step five.