What you're doing right now is absolutely fantastic and you're one of the examples who is immediately off to the races! In terms of own content, technically a source link is not required however it is always good to put a few words to that possibly by saying "Photo I took of ... [Insert Object here], showing [whatever the image shows]", Basically like captioning in Journal format. (You obviously don't have to do this, but I think it's quite a simple way to make an article stand out and makes it easier for reviewers to realize that it's your work and doesn't need to be accredited).
In terms of Curie and Randowhale, I wouldn't worry too much about them, if you keep your content consistent and as brilliant as it is now, then I'm sure you'll be going a long way :D