I was wondering if it is possible to post pictures in comments? It might be useful for clarification of difficult questions. If not then could it be a feature?
It's not possible currently, but we can leave it here tagged as feature request. The site developers monitor questions tagged as feature-request so they will see both this and the votes that people have left for the feature to be implemented.
(Don't be alarmed if people down vote it - votes here work differently than on the main sites)