First question: You'll get better results by asking someone who does know what's on the server. If GD Lib is configured it will show up in phpinfo()'s report. Imagemagick does not have a PHP extension.
Second question: assuming GD Lib is installed, it's not loadable from .htaccess, but may be loadable at runtime with [man]dl[/man]. Security issues may mean that this function is disabled on the host. Again, ask someone who actually knows.