Well dude, an isolation transformer is a big heavy metal block. So picture #3 looks like it. But like you said yourself, in picture # 2 there appears to be something like that too.
Your best bet is to look at the wiring that comes from the monitor. Trace (follow) where those wires go to. There should be two or three wires that are the video signal, and then there should be two wires that are power and power ground. Try to find those leading to one of those transformer blocks.