How do you use "textures" on pictures?

Question: How do you use "textures" on pictures!?

like these:
http://flickr!.com/search/!?q=texture&w=13!.!.!.Www@QuestionHome@Com

Best Answer - Chosen by Asker:

There are many ways, I used them for an old fashioned look in this picture http://www!.flickr!.com/photos/perki88/220!.!.!.
You copy and paste the texture onto your image and change the opacity of that layer!.Www@QuestionHome@Com