findin colors in gif files

hi everybody, i am new to this list & php and i have a big question that i would love to be answered ;) i have a small gif file that has a part in #ff3366 colored - so what i thought is to do a mean hack for my website: instead of opening all images in a graphicseditor and change the color manually i could look up for that color (ff3366) in the image files and replace it with something else, unfortunatly i got stuck with this approach pretty soon. here is my problem: if i open the gif file in php (its attached to this mail) and convert it to hex: $filetext1 = implode("",(@file("vcd_1.gif"))); $filetext1 = bin2hex($filetext1); } like this i get a string that looks like hex - but i cant find my ff3366 anymore, did i miss something really obvious? if i look up the gif file with an hexeditor (i use textpad) i can see it - with php its not findable any ideas?