Most of the time, a role is merely a hint to tell the presentation layer how to style an element. It's up to the presentation layer to act on that hint. In the HTML output, that acting is performed by the stylesheet (i.e., CSS).
The default stylesheet that is bundled with Asciidoctor applies the following rules to the thumb role (i.e., CSS class).
And still looking at the output html/css there is zero difference.
I will really appreciate if you post a screenshot of the same image with and without "role=thumb", to see the effect
because looking at the css snippet it might be exactly what I want.
Thank you , you all been so helpful.
While waiting for reply I applied the css manually :)
I will bring the issue to gitbook, but I don't think it will resolved anytime soon.
I also tried orher roles from the guide , only one kind of worked
- positioning right but only with _block_ images (::).