I inserted a corresponding AllSky image in each comet image. Within each Allsky image is a small circle marking the rough location of the comet during the exposure. I also annotated each comet image with Sky quality readings. Interestingly there were high clouds making the sky slightly brighter during the Lovejoy image than the ISON image, this is evident in both the Allsky image and the SQM readings.
Image scale is preserved but the screen stretch is not.