Okay now your going to change the hue and saturation, but don't fret I have the settings for that right here, or you can play around with it a little ...
I was messing around in photoshop making a gimp care bare (as you can see in the background of my photoshop. LAWL.) and I came across a nice way to make a blood background maybe for a signature or avatar or what not and I'll teach you how to make it!
Step 1: New Document
Okay, you're going to start off by creating a new 5 inch by 5 inch document.