Here this is a pretty simple question but it's been pissing me off no end, I'm trying to get a title image to display on my imageboard, the image is uploaded to the /wakaba directory and I've pointed at it in config.pl like so

use constant TITLEIMG => 'header.jpg';

The pic being named header.jpg, obviously. I've googled this many times and this thread just keeps coming up, nothing in documentation anywhere else. Is therre a pixel or size limit on the pic that's not mentioned? Cheers.