With the DIPAPI32.dll available from the MS knowledge base it is possible to capture a window and save it to a BMP file.

then you can use the append general command.
i'll search in my library for more information. I made a program which can capture a video image. convert it in to 256 color (palleted) BMP format and append it to a table.

Hint: the Wang Image Edit control OCX (in your Windows directory) contains some really nice functions for handling BMP's.