The issue with the image is that the background is transparent.
Hahaha lol, that joke was transparent enough
@fenster: your drawing does not help me: are all of the cams placed "outdoor"? Then it might help to draw "doors" and "windows", as most burglars cannot run through walls. However, if you have single floor buildings, you should eliminate blind spots are some of the more athletic pino's are climbing up from such a blind spot, and may enter your buildings from a light corridor/roof window. That's why IPCT advices the IPVM calculator: you can see the field-of-view of the cams, to verify if you will run into blind spots (especially around doors/windows) and verify your required DORI distances. As a general rule of thumb: where cam-A's field of view "ends", there should be a starting field of view from another cam-B. And if you are really paranoid, you could make sure that each cam sees another cam (to verify if someone is breaking it down). But watch out that the IR beams are not blinding each other. All depends on the "what" you want to see, versus the "how much money" you want to "invest" in it.
Hope this helps!
CC