Which distro are you using? Also if you installed GD enabled version of php5 binary (and didnt compile) you would need to restart apache for it to take effect. I notice that your phpinfo file entry for GD only has about half the available supported options enabled. No Freetype. Try enabling all the options in GD. It works fine for me using debian with all options enabled. Check your logs also.

A full GD:

And working on my site:

http://grognard.sytes.net/forum/index.php?mode=contact