So I created a gallery, to see if it was a permissions problem, which worked. And was then able to upload pictures into it.
Is it not possible to upload pictures without having a gallery to upload them into? From reading entries here it seems like that isn't the case, and if it is the case it might be useful to make that explicit in the documentation. Was it just LJ taking it's time to set up all the permissions for my account? I imagine that there'll be quite a few automagical processes that need to be undertaken before people can upload piccies.
Secondly, I tried to modify the "Tab" colour in the "Portfoloroid" style (Edit Layers) by clicking "Choose" and it took me back to the Edit Style screen.