On relatively low load FunkyBackgroundGenerator blocks on generating random numbers using SecureRandom. That problem makes FunkyBackgroundGenerator unusable for web-applications with more of less high load. On linux SecureRandom class is approximately 50-100 times slower than Random class. It can be even worse if '/dev/(u)random' is used hardly for some other purposes or application itself uses SecureRandom in other places.
I believe that for background image there is no harm in replacing SecureRandom with Random and user SecureRandom just to generate a seed.
any linux, tested on redhat and fedora.