Currently, BLOX CMS allows for certain story blocks to have image previews which are cropped to a specific aspect ratio, which improves the look at feel of the site on the front end.

However, if a site admin wants to adjust an image that is being automatically cropped due to aspect-ratio preview size settings, it is somewhat difficult to guess how big the image should be in order to create a preview which isn't cropped.

New fixed-ratio cropping tools
Preview aspect ratio settomgs in the General design panel