I wish this helpful for you Assuming Evince uses GIO (I failed to find a way to quickly browse its code), you can use e.g. g_file_query_info() to get a GFileInfo pointer. You can then use g_file_info_get_size() to get the size of the file.
This might help you Is there a way to configure nautilus to open a file into an existing gvim process in a new buffer instead of loading a new instance of gvim? I know I can drag and drop the file into gvim, but it would be convenient if I could just double-click a file to open it. , In a Terminal
Name=GVim Text Editor (Tabs)
Comment=Edit text files in a new tab
Exec=gvim --remote-tab %F
Right-Click in a text file
Open with a another application
Select "GVim Text Editor (Tabs)"
To fix the issue you can do No, not with the extension interface. The canonical way to create individual icons is to register a so called "thumbnailer" in the gconf database under /desktop/gnome/thumbnailers. For ID3v2 APIC frames, solutions are already available.
How can I get the resolution (width and height) for a video file in Nautilus/Caja linux file manager?