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What does the size of the Gallery Stats boxes mean?
The size of the Gallery Stats boxes id determined by two things. The width is determined by the number of comments and the height is determined by the number of favourites.
The more comments a deviation has, the wider it will be. The more favourites it has, the taller it will be.
The size maxes out at 200px wide and 200px tall, so the ideal deviation is one that is quite squarish, meaning that it has a lot of comments and a lot of favourites. A deviation that is tall and skinny means that it has received many favourites but not as many people have actually commented on it. Likewise, a deviation that is wide but short indicated that it has received many comments from viewers, but not many favourites from them.