First, sometimes scrolling through the choices will result in themes which are unusable. In the first screen shot, I have scrolled through and found a theme I want to try out. Everything looks OK but it wasn't what I was looking for. I scrolled further down and came across another template to try out... but it is broken. It doesn't work. The "body text" and "author" boxes are missing. The theme is blank. What gives? [:s]
Second - The aspect ratio SHOULD be on the left hand side above the thumbnails. The thumbnails should be shown in the chosen aspect ratio.

