Thumbnails of images larger then 10MB are not displayed

There is a setting in Nautilus (the file manager) that you can change.

1. Open up Nautilus.

2. Go to Files > Preferences.

   

3. Go to the Preview tab, and change the "Only for files smaller than 10 MB" setting to the number you want.

   

   You can choose from 100 KB to 4 GB (in pre-defined increments).

   

As I'm using xmonad as a window manager, I have no "file" menu in Nautilus (or I don't know how to access it).

I managed to change this setting using the dconf-editor. Here is how:

1. Open dconf-editor
2. Navigate to org - gnome - nautilus - preferences
3. find the key "thumbnail-limit" (was set to 10485760, the default I presume)
4. Change that number according to your needs.

The size is in bytes, so if you want to preview pictures that are 20 Mb, put 20971520

While you're at it, you might want to change also the value for "thumbnail-size" (org-gnome-nautilus-) to 128. This will turn nautilus into a photoviewer (zoom with CTRL-scroll)

Likewise, you could change this setting from the command line using dconftool