Image editing - Copyright?

Hello,

Can I edit, photoshop etc. celebrity photos and then post them publicly?

Is this legaly ok for me, or do those people have any leverage over me, can they sue me or something like that?

It depends on the license type

You can go and search Google for "some person", click image copyright -> Reuse with modification and use it.

It really depends on the context. If you're altering the image substantially and creatively, and not making money off of it, then you're okay. If you alter the image and start making money off it, or using their image to promote a product they're not in on, then hopefully you don't get caught because that'll be a breach of various things like privacy or publicity laws / the photographer's copyright / potential trademarks / etc. If you're using the image to prove a bigger point involving facts or political / social / historical critique, then you should be protected under various laws. Also depends on what country you're in. Not sure what the copyright law is in Rainbowland