Changing black to blue (2)

Hi there, I know I already posted this prob 2 days ago, but I am still stuck. What I tryed is to use imagefill what BvR suggested, but the problem is, that I would need to know where the black part is to set the start pixel color. This is not possible. Also Hugh was asking why I do not do this in Photos. Thats because I have 250 images and don't want to save the same image twice. There must be a way to do this in php. The sittuation is as follows: I have a map of the world with all countries. I have 250 maps of the same size as png where only one country is black, rest is transp. Now I neeed to set this country color to blue or red to indicate a special spot. I just don't want to save the same map double or tripple. How could I color the black spot inside the transparent png? Thanx a lot for any hint. Andy PS: The old message is underneath I would like to change the color on a png file from black to blue. This png file is transparent and contains only a spot which is black. It is needed to stay transparent because I am gonna merge it later on with a jpeg. I tryed imagecolorset but anyhow I do not understand the syntax. Here is my try: # set home color $farbe_b = imagecolorallocate($country_image,0,0,0); // create index for the black color imagecolorset($country_image,$farbe_b,51,51,204); // darker blue Can anybody help on this. Thanx in advance, Andy