Blood Splatter
In order to create a good looking blood splatter,
your going to want to open up a decent image editing/creation program, i prefer MSpaint.

Be sure its 32 x 32.
Choosing the right color
OK, now we are going to find a color that fits the game, or feel of the blood you want.
The first thing you should do, is find the BASE of the color.
The base of the color will fill the white area.
like so.

I have chosen a simple red.