Hello Minhcom,
Are you sure you are working with CMYK bitmaps? CMYK has 4 color channels, so it usually occupies 32 bits. Anyway, GDI does not support any CMYK pixel formats (at least officially).
If you mean RGB, you can do it with Graphics Mill.
P.S. Note, Graphics Processor is discontinued product. You should use Graphics Mill instead (unless you have a lot of legacy code with Graphics Processor).
P.P.S. If you have any questions regarding Graphics Mill, please post a message to Graphics Mill forum.
Sincerely yours,
Andrew Simontsev from Aurigma Team