add event image URL to iCal (.ics) exports
The iCal format supports attachments (using URI or BINARY/BASE64) so would be very convenient export also the URL of the cover image (if present).
Example:
BEGIN:VCALENDAR
CALSCALE:GREGORIAN
VERSION:2.0
PRODID:-//Elixir ICalendar//Mobilizon 1.1.4//EN
BEGIN:VEVENT
CATEGORIES:
DESCRIPTION:bla bla bla
DTEND:20210824T120000Z
DTSTAMP:20210816T105421Z
DTSTART:20210824T110000Z
GEO:45.123;11.123
LOCATION:address
ATTACH;FMTTYPE=image/jpeg:https://mobilizon.it/media/**image_id**.jpg?name=*number*.jpg
SUMMARY:bla bla bla
UID:*uid*
URL:https://mobilizon.it/events/*uid*
END:VEVENT