I guess you'd have to do that yourself. One thing you could do is reserve one colour like purple (255,0,255) and replace it with other colours for all your different monsters. But you'd need to change hue if you want to change your whole monster to another color.

Convert RGB to HSV:
http://delphi.about.com/od/adptips2006/qt/RgbToHsb.htm
Convert from HSV to RGB:
http://www.delphipages.com/forum/sho...d.php?t=133111
More info:
http://www.efg2.com/Lab/Graphics/Colors/HSV.htm

So just write a function that takes one pixel as input, converts to HSV, changes hue, then back to RGB. Call it for every pixel and you're done.

One cool variation would be to use a mask. That'd give you control over which area's of the picture must be changed and which will have the same color.

Good luck!