Note that read_filelist used to check if its argument was an image (for people
accidentaly typing "feh -df *" instead of "feh -dF *"); this was removed
because it failed on /dev/stdin.

I might re-add it, but I'm not yet sure about the future of feh's automatic
filelist saving.

It is pretty random and I doubt anyone actually uses it. Also, after removing
it, there are only two duplicates of the image index code instead of three...

By default, feh draws white text with a black drop-shadow, which is well
readable in most, but not all cases.  The --draw-tinted option draws a
semi-transparent black box around all texts.  This improves readability, but
does not look as nice, so it won't become default behaviour.

It was suggested to use #7f7f7f7f for the background, but I decided that
for small images surrounded by a black border.

An action may be used to alter the image or specific parts of it displayed by
--info, so if a user invokes an action with hold_action set, the image and all
relevant information must be reloaded.