dBfast - Graphics Windows

i have developed a small utility to display BMP files on various notebook with different resolutions to mantain GET and Say always in the same point on the graphic image use as background.. After many testing ( with WinHex) I found that the standard risoulution (96 DPI ) may be changed at byte 38 and. byte 42 of the image file (default value 196 - 14
Hex C$ - 0E