compiling problems: imlib 1.9.4

[Olaf Grüttner <O Gruettner tu-bs de>]

hi, 
I am having compiling problems with the imlib 1.9.4 
library.

the make process breaks and demands a png.h file.

I searched with 
find /usr/ -name "png.h"
but with no result

is it hidden in some other file?
where can I get it?

thanks
Olaf