welcome to the steemit community and may i say that some of those photos are very interesting. there are a few unwritten rules that you should be following if you are to join a community. The basics would be on your sources. As you might have already be aware that you can upload images that are on the internet straight to the post but the community does not take that lightly, remember to cite and give credit to all your sources before posting, be it an image, a graph or anything that you obtain from an outside source or not made entirely by you. the most important rule to follow is to be nice and be polite.