I only used the spraypaint tool to simulate blood, and my only MSPaint creations to feature blood are my Stick Figure Death series (entitled Done) and my now famous Head-wound Smiley. Oh, and I used it for the puke in my reenactment of Shawn Puking. Like I said, that picture looks grainy because of the compression artifacts going from a bitmap to a GIF, and I think it looks great.
And KDR, I'm perfectly happy with my MSPaint work so I see no need to learn drawing. I am a follower of the mantra "Simple yet elegant".