Need to add common "C" for thermostat; can anyone indicate where to connect it?
First of all, don't make any assumptions about wire colors. There is no standard, everyone does it differently.

Secondly, there is a very clear C terminal in your picture, at the bottom right of the control board. It also looks like you have an air conditioner connected. 



This "blue" wire you're talking about looks like it's not connected at the board. If my assumptions on the wires are correct, then all you need to do is connect the blue wire to the "C" terminal, and you'll have a C wire at the thermostat.

If I'm wrong about anything, or just for more background, you can refer to our go-to thermostat-c-wire question: How can I add a &quot;C&quot; wire to my thermostat? (or read any of the other questions with the thermostat-c-wire tag).