Unlikely we ever support conversions with compressed image format.
Define is a bit ugly I guess, but nicest way I could think off.
Can probably be used in some image writers as well, have to check which support/don't support compressed formats first.
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6042 dfc29bdd-3216-0410-991c-e03cc46cb475