Photo Editing Service

unicorn97

Hi, I hope this is the right forum for these queries I have.

I am looking to turn a hobby of mine into a mini-business.
I like to edit photos using photoshop and have become quite good at it, and I'm looking to branch out and offer my skills as a service.

Now i don't come from a photography background so i'm not sure about the laws around copyright and I 100% do not want to be in breach of any laws around this.

My understanding, and correct me if I'm wrong please, is that if a customer provides me with images to edit that they own, that's fine and can be used for commercial use if they wish.

If a customer provides images for me to edit that they do not own, or have taken from the internet, this is copyright, and can't be used for commercial use?

I'm hoping somebody can clear this up for me, as I want to follow the rules.. :P