Staff Pics are a real thing.
There is no official channel for showcasing a book to the Tapas Staff as far as I've seen)
-- and probably should not be considering that we're talking about a small staff. Reading all those submissions would become their full time jobs.
There might be a contest/event near the end of the year around NaNoWriMo time in which the staff specifically reads in order to recruit new writers into a promoted category, the Premium Series. Some years that happens and some years it doesn't.