You can customise villager chat with your own images by using the settings in the newest versions, if that's what you mean? Info on that here: https://forums.slime2.stream/resources/villager-chat.9/field?field=customization
If you mean something else, could you explain?
I tried placing an icon in front of the name, and it worked.(just for ver1.1.0)
I feel that adding this icon makes the overall appearance look cuter!
However, I'm unable to open the HTML webpage to make other adjustments.
(Because I have no understanding of CSS or HTML at all.)