There is not set number of allowed colors, we only want to make sure that the posted images show pixel level control. 3564 colors suggest JPG compression, as IllusionOfMana said.
This has far more than the maximum 256 colors allowed per piece. Please revise this submission with a non filtered or JPEG compressed image if you want it to be considered for the gallery.
oh wow, I wonder where I got the 256 color limit from XD maybe another forum.