Not sure if this is the right place to post.
I'm using the Office RibbonX Editor to customize the ribbon on my word template. I would like to be able to change the icons of the galleries I've used.

Each time I try to change the image with one of my own inserted icons the icon doesn't change.

Below is an example of one of the galleries. Could someone help?

<gallery idMso="CustomAutoTextGallery" label="Lunge" imageMso="Lunge" size="large" />