If you save the image file as a bitmap, it's somewhat easy to extract the pixel bytes. Look up the BMP file format on common Windows API sources. Chose the lowest color depth and intensity (b/w) encoding and no RLE compression, then you may get the desired values without further conversions. In any encoding you'll have to strip the BMP header bytes from the file, which indicate the file format, number of colors, color depth, number of rows and columns etc.