I'm using Delphi7 and VFrames (TVideoImage) with this Procedure 

```
uses  VFrames;
....
procedure TForm1.snapshot;
var
cam:TVideoImage;
strlst:TStringList;
BMP:TBitmap;
begin
strlst := TStringList.Create ; 
cam :=TVideoImage.Create;
cam.GetListOfDevices(strlst);
cam.VideoStart(strlst.Strings[0]); //specify a cam by number
//get snapshot
BMP := TBitmap.Create;
cam.GetBitmap(BMP);
BMP.SaveToFile('test.bmp');
cam.VideoStop;
BMP.Free;
end;

```

Result blank Bitmap file.