Mah, con le GD ho sempre lavorato... dunque il mio php.ini nelle GD ha:

GD Support enabled
GD Version bundled (2.0.34 compatible)
FreeType Support enabled
FreeType Linkage with freetype
FreeType Version 2.1.9
T1Lib Support enabled
GIF Read Support enabled
GIF Create Support enabled
JPG Support enabled
PNG Support enabled
WBMP Support enabled
XBM Support enabled

gettext
GetText Support enabled

E' sufficiente?