Change the image of custom layouts

Hi, I have followed the tutorial to create new custom layouts in Bloomreach Define a Custom Document Editor Layout - Bloomreach Experience - Headless Digital Experience Platform

I have a problem with the layout icon. The following images are displayed:

and I have these two defined:

Each one on its own route:


How does this treat the images? do you have to compile something else? I have added the following in the pom.xml of the cms:image

I remember to have a similar issue in the past and for me it was a browser cache issue. Can you check?