Listing Detail help – photos upload & height of left side bar

I went live yesterday and people are now starting to add business listings. A few issues:

The photos they are uploading are not appearing and the featured image is not appearing.

I understand that they need to be a certain size however, if an external person is adding an image from the front end – are they prompted of this – how do they know the image needs to be a certain size.

Also – how to I increase the heigth and the width of the details side bar as it seems to be cutting off some of the details.