A friend directed me to JacksonPollock.Org, a site where even babies can create artwork. With just clicks and movements of a mouse, you can change spatter size and color. Plus, the site doesn't seem to require much from a computer to be enjoyed. No need to install, pay or subscribe to anything. For sure, your mac memory can handle it. You may need to do a lot of print screens though so you can save your masterpiece.
This is a really nifty thing to distract kids from tantrums with.