fatal error on install

... and what does the rest of the error message say?

Odd. I would have expected it to say "hex_to_rgb() already declared in ???"
Where xxx would be useful to know.

It seems that some other module has also been lazy and left off the module name as a prefix - which is the convention.
So at the moment this issue is a conflict with ???
It can be fixed at this end. I'll tidy it up some time.
In the meantime you can either id whatever is conflicting, or as a quick hack, wrap that function (in link 128 utility.inc as it says) inside

if (! function_exists('hex_to_rgb')) {
  function hex_to_rgb(
  ....
  }
}

... although that may not work as expected. Need to know where the other declaration is.

Cool, that's an answer.
We are both being badly behaved modules.
... at least I only declare that function when I'm actually building the image :-)

I'll rename the func better in dev sometime.

Renamed, and using the imageapi hex function where I can