search for: rgb3toppm

hi, one pretty small question .... i wanted to create my own mini-distribution, using syslinux to boot the system. Everything works pretty fine, but now i wanted to see a graphic on boot time. :-) I saw i have to create a graphic with the file-extension .ppm ... but please tell me with which programm i am able to use such an extension? gimp? dont think so ... hope to hear of you ... thanks in