Look at EnumFileFormats for details.

function ImEnumFileFormats(var Index: LongInt; 
                           Name: PAnsiChar; 
                           DefaultExt: PAnsiChar; 
                           Masks: PAnsiChar; 
                           var CanSave: Boolean; 
                           var IsMultiImageFormat: Boolean): Boolean; cdecl;

ImagingExport (at line 62)