2005 called. It wants its numbered file names back.

While I am mostly satisfied with "celluloid" as a worthy successor to xplayer, the first major disappointment I stumbled upon is `celluloid-shot0001.jpg`. Are we in 2005?

Just like xplayer, Celluloid, the new default media player of Linux Mint, should use proper, i.e. time-stamped names such as `celluloid-2023-04-10T00-47-42.jpg` or `celluloid-video_file_name-2023-04-10T00-47-42.jpg` for screenshots taken from videos, to eliminate the possibility of file name conflicts if files are moved into other directories, to make screenshots searchable by video file name, and to retain the date and time information if the files are moved to a device that does not support date and time stamp retention such as MTP (Media Transfer Protocol), and to allow for date range selection using wildcards in the terminal (e.g. `celluloid-2023-04*` for all screenshots from April 2023). Besides, PNG screenshots should be supported too, but that's out of scope here.

As a reference, the gnome and mate screenshot tools also pre-fill time stamps into the file name field.

Numbered file names were useful in an era when there was no VFAT and file names needed to have 8.3 file names that could impossibly fit a date and a time, and compact cameras used such names, but those times are long over. Just like the useless and annoying pull-to-refresh gesture on mobile apps and the Media Transfer Protocol, numbered file names belong to the technological graveyard.

If numbers are really desirable, at least `celluloid-shot0001.2023-04-10T00-47-42.jpg` should be used, to include both a number and a date. The command to get this date format is `date +"%Y-%m-%dT%H-%M-%S"`. For compatibility across operating systems, dashes instead of colons have to be used to separate hours and minutes and seconds.

Numbered file names are a thing of the past. Use time stamps.