Image copyright. Am I doing it wrong?

I am creating FREE templates. I usually have a slideshow and I would like to know what kind of images am I allowed to use. And how to use them properly?

1. I take the images from Flickr.com that have creative commons license with attribution? I usually watermark the images with the profile link of the original creator. Is that ok?
2. Am I allowed to use gaming wallpapers? For example Call of duty with the name of the game on it. For example this?

I know about sxc.hu, but there are too few images.

 

1) it's ok 2) you may be infringing the copyright using the game's name, I'm not sure

 

Thank you.
can somebody else confirm 1) ?

 

just read the CC rules, it's all there edit: now I see, you're just too lazy to check it yourself, you can keep your neg rep