Why do tiles have such big alpha? Wouldn't it be better to crop canvas to it's content?
Viewing post in Isle of Lore 2: Hex Tiles comments
The idea was to make overlaying images (like borders, locations etc.) easier and more consistent, especially in respect to some tile mapping programs where you have a fixed tile size. That means you could switch out tiles with different borders and apply location overlays without having to change anything regarding their size or positioning, as everything is 840x840px.
Do you need help cropping them or was it more a question out of curiosity? :-)