If you're seeing two images, you're using the old version. Old version is drawing pictures using RGB565 which is two bytes per pixel, but 4.2.8432 firmware switched to RGBA which is 4 bytes per pixel. The 2 bytes vs. 4 bytes just happens to result in image appearing twice but smaller with the old version of pngshow. Actually it's amazing that you're getting this far, it should already fail at the scanline step.
The version you should be using is on the previous page of the thread:
https://www.mobileread.com/forums/sh...04#post3463704