I am trying to make my own layout - I see nowhere on this game of what the required/recommended layout size actually is. Could someone please tell me? All I know is that they CAN NOT cover the navigation tab, footer and activity, animal, event and achievement tabs. 

Thank-you! :) 

We don't have any official requirements on the size (but as you mentioned, those things must be showing!). I'll bump this up, though, since someone might have some input on the ideal size!

I think it's all personal preference. For me, I like the picture to be big enough to take up the screen, but you can see it on one scrollable page, so not so big that you have to scroll up and down to see the whole image.