There's no nice way of putting this, but: Don't be art thieves! This include those of you doing photo manipulations. Don't. Be. Art. Thieves!
Photo's are art as well, and using it without permission is art theft and against DeviantArt's rules.
I know it's not always the popular opinion, but this group will reject images that clearly break DeviantArt's rules. And that include Photomanipulations obviously using photo's without the copyright holders permission.
I ask that you respect these rules when submitting content to this group. So again, I will reject this sort of images if obvious cases of art theft are happening.
I strongly advise people doing photo manipulations to state their resources and prove they in fact are using legal stock images for their art.
There's a whole bunch of this on DA alone, and often it's in nice high resolution, helping you to create high quality photo manipulations.
Following this date, photo-manipulations not stating their resources will not get featured in the featured folder on pure principle.
Here's a few DA FAQ-answers on the topic:FAQ #217: What are "Stock and Resources" and can I use them in my submissions?FAQ #157: Can I use things created by other people in my submissions?FAQ #193: How do I prove that I had permission to use someone's work?FAQ #257: What sort of permission do I need to use someone else's work?
TLDR: Don't use photo's that are not legal stock in your photo-manipulations. This includes popular photos, movie posters and non-stock celebrity images.