How do I make my icons bigger?

I'm not quite sure what the official term is, but when you select an object, in the upper-left corner of the inspector, next to their name, there is a little drop-down box where you can assign an icon to an object. This is very useful for objects that don't have any actual appearance inside the level because I can make them appear as a little gem or a bar with their name printed on it.

The problem is that as I zoom the camera out, these icons disappear way too early. At the point where I am normally viewing the map of my whole area I can't see them anymore, and that's just when I need them the most.
Is there any way to make them stay visible when I zoom out further? Like change their "size" that they are viewed at (but not in screen-space)?

 

Thank you!