Hi Paul,
Those two backs were essentially the same. The Valeo 22Wi came out shortly after the Valeo 22 and they shared 97% of the components, with the 3% being the Bluetooth antenna with the supporting PCB and the casing with the Wi badge on it
Difference in image quality may come from different iso, difference in ambient temperature and software used. Also ensure that the cooling fan was working properly
Hope this helps
Yair