I strongly suggest putting an image placeholder in every place until the image for that place is loaded. The first day I joined I wasted a lot of mushrooms because I didn't realize that skipping quest time cost a mushroom, and refreshing the store items also cost a mushroom, and this was simply because the mushroom image on the button hadn't loaded. In the last 4 days I have been able to quest for exactly 4 items, one of which was the first dungeon key (and two of which were in the same set of 3 quests, so I couldn't even get both of them!). This item rate seems very much too low to me, and I'm wondering if the problem is that the item images in quests are not loading within the 30 seconds I allow for them to do so.

The other thing I would suggest is that the server code for the "OK" button be made unique per screen where it appears. Yesterday after a fight in the arena, I wanted to go work with the city guard for an hour. I hit OK on the city guard screen, but due to some lag issues I instead spent a mushroom and fought another random guy in the arena (and lost just to make it worse). It would be nice if that didn't happen again.

Maybe just save ALL images on the local machine!