I’m unclear how to submit photos to be considered for photo of day/week/month. Or is it the case that all photos submitted are considered?
There are no daily/weekly/monthly/yearly competitions on Telescopius. The date filters on the Astrophotography gallery page is just to see the most popular work in the last 1/3/6/12 months.
At any rate, please remember popularity based on votes, comments, etc. should always be taken with a grain of salt, because it largely depends on the followers each author has, where users post links to their Telescopius page, etc.