How to modify a brush located in the HUD from the main editor ?

Hi everyone !

Here is the context : I want to simulate a museum where you can interact with the paints. I explain ; When I click on a paint a menu appears on the HUD with the paint in full screen and some other specifications. I made a blueprint with the paint applied with a texture and a widget with my picture applied in a brush type (the “picture” refers to the paint). Until this point I don’t have any problem my menu appears when I click.
But I want to use this blueprint for several paints, that means changing the texture of the paint and also the brush of my HUD that has to be the same as my texture. Here comes the issue : I did it well for the texture of the blueprint, but no way to find how to change the brush for my HUD from the editor … I tried but nothing happens, I link what I did.

I link some captures to be clearer, I am french so sorry for the variable names. I hope it was understandable ^^ Ask me otherwise !

In “Perso” I can change the blueprint texture called “Image Tableau” and the “Image tableau HUD” should be the brush linked to my HUD, but when I change it nothing happens in my HUD.

The construction script of my Blueprint ; in red is what enables to change the blueprint texture (no problem with that), then in blue the variable “image” comes from the widget “Navigateur” (see third picture), I try to apply to it the brush I entered in “Image tableau HUD”.

I put the previously defined variable “Image” in the brush of my picture, so it would change the big white square we see, but this big white square stays here …