Do we have a reason that thumbnails aren't shown in the sidebar of chat? I noticed that they aren't shown in the sidebar, but are shown in the list of all starred posts. Why is this? There doesn't seem to be an obvious reason. Can anyone tell me why?
Mainly because of the space involved. The sidebar is significantly smaller and only meant to get a brief overview of links. If it is an image, in order to make the thumbnail fit it would need to be smaller than the standard scale of thumbnails in chat, meaning it would be almost pointless as the thumb would be too small to be any more relevant than the links to the image.
If we were to increase the size then we would make the sidebar post bigger and push other starred posts off the list (which already happens as it is with starred posts in the sidebar only being in the past 24-48 hours.)