The Theme Preview Thumbnail is distorted. Please can we make it proportional by width, which will prevent distortion as well as cropping. Normally the thumbnail for a website has a variable height, some previews are short and some are longer.
Crop theme preview images so they are not being distorted (see #4361)
Fixed in 7df126e. I prefer to crop the images though, because this will keep the line height of all entries the same and make it easier to navigate.
perhaps we could have had a image size variable in the Theme, so specify width/height/mode, so the user can decide. I do like your center_top mode, as it’s better than a center crop.