(Asus EEE netbook, Mint 13, Backports repo for Cinnamon 2)
Thumbnails should display in Compact and List views as well.
I have the same or a similar problem, and it doesn't appear to be a settings or permissions issue, at least in my case. I have both Nemo and Nautilus. Both are set to display thumbnails, and the ~/.thumbnails folder has read/write/execute permissions for my user. I open a folder full of .JPGs in Nemo, and there are no thumbnails in any view setting; I see only generic image icons. I open the same folder in Nautilus, and the proper thumbnails are shown there. Now if I reopen the same folder or refresh the view in Nemo, it does show the thumbnails. So Nautilus is creating thumbnails as it should, and while Nemo is displaying the thumbnails generated by Nautilus, it is not creating them itself, or is confused about where it is creating them, as I suspect because:
In addition to ~/.thumbnails, there is also another folder, ~/.cache/thumbnails, in which Nemo does appear to be generating thumbnails. If I delete both of these thumbnail folders and then open the image folder with Nemo, the ~/.thumbnails folder does not reappear. The ~/.cache/thumbnails folder reappears, and has the expected thumbnails in it, but the thumbnails do not show in Nemo until I view the same folder with Nautilus (at which point the ~/.thumbnails folder is recreated) and refresh the view in Nemo. So, is Nemo generating its thumbnails in ~/.cache/thumbnails, but looking for them in ~/.thumbnails instead?