Code:
'The declarations is the following
Private Declare Function BitBlt Lib "gdi32" (ByVal hDestDC As Long, ByVal x As Long, ByVal y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal dwRop As Long) As Long
'and here's how to use it
    BitBlt DestinationDC, destX, destY, Width, Height, SourceDC, SourceX, SourceY, vbSrcCopy
you'll find lots of sample code by searching on bitblt.

The DC's mean device context and are usually connected to the bitmaps already, most controls like pictures and forms have them already as hDC property. use those.