I suggest changing your previev to at least a more high res one, as at the moment it is one of the most repulsive previevs I've seen during this Jam.
Viewing post in Hullu Lohi jam comments
yeah I know that the resolution of the picture is terrible and that it is even stretched, but the GameJam is over and since we decided to spend our last minutes of the GameJam to fix those last bugs in the game instead of creating a better preview image, we have no better picture. Like I said in the description, this was our first GameJam and we were not familiar with game development at all. We learned many things, so next time there will be a better preview for sure:)