Creates an IupImage from a native image handle.
Ihandle* IupImageFromHandle(void* handle);
handle: a native image handle, such as the NATIVEIMAGE returned by IupClipboard.
Returns: handle of a new IupImage, or NULL if failed.
The native handle type is driver-dependent (GdkPixbuf*, a DIB HANDLE, QPixmap*, and so on); see NATIVEIMAGE in IupClipboard.
The pixel data is copied into the returned IupImage; the source handle is only read, so the caller keeps ownership of it.