Putting individual images over children

Hey ho,

I feel Ive fallen into a corner of youtube tutorials that no longer reach this dark place lol.

Essentially I have a list of achievments placed by an array/sizebox and adding child to populate the achievments list.

When an achievment is achieved, Itd like to overlay the child with an image to show its done. However I can either make it visible for all of them, Or none of them.

This is essentially where Im at right now? Is there a node I can research? Or anything Im missing.