Certainly, old chum. It's not really that much more complicated than the few explanatory lines of the very first post in this topic, but, to elaborate just the same...
The general idea is to find inspiration from the picture, which has been chosen by the previous 'winner' (that's to say: got the most votes, although, everyone is a 'winner', really ... ). The composition can be in any genre, played with any instruments, real or virtual (so not just bass, although it can be..!). Recorded by any means available, however modest, by yourself (although backing vocals, 'guest' band members, passing refuse truck etc... are tolerated...). The composition must be in the current month, and the resulting file would normally be posted on Soundcloud (it's free, for modest use of the sort...), before the closing date, which is normally about a week before end of month. Once closed, a 'Voting' topic is posted, inviting BassChatters to vote for their favourite(s), and at month's end, a winner is declared.
Not much more to add. The absolute quality of playing the production quality, the instruments used... None of that is of great matter, as the 'judging' is based on the aptness of the music to the picture (at least in theory, although the criteria behind the voting is up to the voters, in truth...).
Maybe the simplest would be for you to have a look at the picture, see what comes to mind, musically, and record something..? Offer it up and see what comes of it. What's the worst that can happen, eh..? It won't be any worse than what Lenny bungs up every month, and my own are often enough complete and utter 'flops', so you'll be in excellent company. Give it a go, lad. You know it makes sense.