The photo that will show up in your list is the one with the most thumbs, theoretically the best photo provided. When reviewing your list, you can click on the specific plant to open the database and see your photo as well as all others. The only time this has been somewhat weird for me is when I have a generic plant in my list, e.g. Dahlia, with no known cultivar. In that case, the featured photo may not look anything like my plant. On the plus side, that encourages me to try to figure out what cultivar I actually do have. Sometimes I cheat and simply tag my plant to whatever I can find that looks the closest (e.g. daylillies which have about a million cultivars), in which case I make a note in my personal comments section that I am simply guessing at the cultivar.
To ID a plant, I think the best place is to post your photos in the ID Forum which is monitored by all sorts of smart plant folk. Rather than cross-posting in the Sempervivum Forum, which tends to be confusing and at times annoying to others, you could place a secondary post letting the Semp folks know that you are looking for an ID which includes a link to the ID Forum. That way all the potential answers would be in one place (the ID Forum).
Good luck with your ID - I look at it as a treasure hunt.
