You are 100% correct, bplus - I was playing around with that older game code and felt it needed something else.
Hmm, I will redo the colors to make them them stand out better. I'll post an update.
Thanks for trying it out!
UPDATE: How about this? I made the yellow image more yellowy. Replace the old 1.png with this one. Hope it's not worse -- on my laptop the colors stand out ok..
UPDATE 2: I just remembered you corrected some colors for a puzzle I did a while back that had this same problem, I'll dig it up and copy those ...
- Dav