How do I make blends using Photoshop images?

I am looking for a way to create blends of different images and brushes for a wavy background. I am able to use the brushes and to crop the Photoshop images but making them blend in posing a bit of a challenge. Further, I would like the photos to assume the color of the background. What this means is that if the background is blue then the photo should appear to be bluish to have it blend in well. Thanks.
