Simple map making help

[Enerath]

Just two things for now,

I've made my own art by cutting the wyvern images from monster and redoing it slightly. This is for my maps.
I've gotten the arch-file to work and got the image to show up in map maker. (Many thanks to Arilou and Teshuvah).

However when I put down the custom image monster it still has a background.
I've tried going into editing software and removing it but it still stays there.

And,
Would it be a "Zoo" if I put my special wyverns in cages in one area for viewing and then later on in a training spot where you encounter them?
You can't open levers and release the wyverns but you can find them later and fight them.
Does that make sense?