Being a photographer I can attest to the fact that any color will take on different hues depending on the light it is being viewed in. We see it all of the time in the photos we take of our spoos. Sometimes they look darker than they really are and sometimes they look lighter. I actually put photos in Lightroom and adjust their color according what it looks like to me in natural light (outdoor with light overcast sky).
Also, not all cameras will make captures in true color so you have to account for that too.
So you dog looks like a light red with a liver nose but in a other lighting it is very possible that he would look either lighter or darker depending on the light source.