Sorry, I meant sprites, not tilesets. For example,
alpine_fauna_leopard_snow_.png is 72x96 ; each "img" is 72/3=24, 96/4 = 24
so each leopard_snow is 24x24 ; this forces some 16x16 only situations to manually pad this to 32x32
Yes, while all tilesets are made with 16x16 px tile resolution in mind, there are 16x16, 24x24, and 32x32 sprite sizes to keep animals proportion as normal as possible. Larger animals such as moose and elephants of course have larger sprites (32x32) to comply with their natural size. Otherwise you will have strangely proportioned animals.
If you use RPG Maker, I don't think there are any issue on using those sprite sizes as long as you use always use 3x4 sprite layout (please see the animals screenshots, all of them are made with RPG Maker).
Ah, so it is not alignment issue, but rather because of cell size I see... If that's the issue I'll consider it for the next updates.
My suggestion for animated sprites is by not relying them to the certain tilesets size, but by height-weight division (row x height = 3 x 4), therefore you don't have to rely on fixed tilesizes (e.g must be multiplication of 16, 24, or 32, etc) when you get your assets from different people with different standards.