Patch to clipboard.rb to copy bitmap to clipboard using the function Win32::Clipboard.set_data(f, Win32::Clipboard::DIB)
or
Win32::Clipboard.set_data(f, Win32::Clipboard::BITMAP), where f is the file readed to a string.

Example:
    # Put the image test.bmp on the clipboard
    #    f = File.open("test.bmp", "rb")
    #    str = f.read
    #    Clipboard.set_data(str, Win32::Clipboard::DIB)