FreeImage_GetDIBSize is available since version 1.0.
Prototype:
number FreeImage_GetDIBSize(number dib)
Description:
Get the size of the DIB-element of a FIBITMAP in memory. i.e. the BITMAPINFOHEADER + palette + data bits (note that this is not the real size of a FIBITMAP, only the size of its DIB-element).
Return value:
Returns the size of the DIB-element of a FIBITMAP in memory.