BEGIN:VCALENDAR
BEGIN:VEVENT
UID:uri
IMAGE;VALUE=URI:https://example.com/a.png
END:VEVENT
BEGIN:VEVENT
UID:binary
IMAGE;ENCODING=BASE64;VALUE=BINARY:AP+A
END:VEVENT
BEGIN:VEVENT
UID:text
IMAGE;VALUE=TEXT:a\;b\,c
END:VEVENT
BEGIN:VEVENT
UID:unknown
IMAGE:https://example.com/b.png
END:VEVENT
END:VCALENDAR