Cape Cod Insulation/Snow Melt
It is very difficult to tell based on a photo. There are a number of factors that could indicate insulation problems and melting patterns is one of them. But it depends on the current outside temperature, sun exposure, how well the shingles absorb heat, wind conditions and how hot the interior is. 

I'd say a better way to determine if there are issues is to examine at the utility bills. The seller should be able to provide them. Realistically the insulation is there mostly to keep cost of heating down so the expense should be a decent indicator of how well insulated the house is. 

Another thing that will indicate poor insulation is if the room feels cold. Let's say the temperature on a thermometer in the room reads 72°F but it is not comfortable. That's another indication that the walls are poorly insulated. It happens because the heat radiated from your body is not adequately radiated back from the wall. You can also place the back of your hand on the exterior wall and quickly compare it to an interior wall. Knee wall cavities are often problematic due to confined work spaces upon construction and limited soffit ventilation. 

If all the houses around have snow on the roof this one is the only one that doesn't, it's probably not well insulated.