Returns an extended attribute. \n
* Returns NULL if not found.
* See also \ref imDataType.
*
* \verbatim image:GetAttribute(attrib: string, [as_string: boolean]) -> data: table of numbers or string, data_type: number [in Lua 5] \endverbatim
* If data_type is IM_BYTE, as_string can be used to return a string instead of a table.
* \ingroup imgclass
Returns an extended attribute. \n * Returns NULL if not found. * See also \ref imDataType. * * \verbatim image:GetAttribute(attrib: string, [as_string: boolean]) -> data: table of numbers or string, data_type: number [in Lua 5] \endverbatim * If data_type is IM_BYTE, as_string can be used to return a string instead of a table. * \ingroup imgclass