How to using GD for PHP?

[vietmodel]

I configured my site to run PHP5 and GD2 (php.ini: extension=php_gd2.dll) but when I call functions like imagegrabscreen() or imagegrabwindow(), i got the error:
"call to undifined function ...."
Please help me to fix this problem.

Thanks in advanced.

[linFox]

Hostmonster use Linux servers, those two functions (and the .dll extension; trying to load it will only cause errors) are Windows-only.
GD2 does however run natively on HM without needing to specify extensions yourself.