The JPG format is of no use for this particular purpose, especially being lossy - the format must be BMP, since it has to be hacked into explorer.exe as the BITMAP resource with ID 157.
Another thing is that the gradient should be calculated so that the bitmap viewed in 4bpp (in situations where video driver is missing or inappropriate) would not "split" the first word or otherwise look unaesthetical.
One other detail, albeit minor, would be resource 161, which is loaded in Safe Mode instead of resource 157. That's a grey-shaded image, much shorter than 157, but nevertheless it could be hacked into showing Second Edition somehow.
I've played with res 157 a few days ago but never got to post the results. Banner3.bmp would be the best bet, since it's the only one that takes into account the 4bpp aspect.
Here you are: download.
I assume that 4bpp means 4 bits per pixel, (meaning 16 color mode I guess?), but I have no idea how to apply that to the gradient or how to force viewing in that mode to see how it looks. But if no one else volunteers, then I'll give it a try, but no guarantees!
Cheers and Regards