I want it so users with 0 posts will x.gif, and users with 25 posts will have x1.gif, etc. So instead of stars under their name they have these images. That is, do not want to use stars but different images.
goto ACP >> User & Groups >> Groups >> Select Group name >> under user stars >> change "images/star.gif" to the url of the image you want.
change the # of Stars to 1 or any desired value
This pluggin puts the image next to the user name, this is not what I'm looking for
In that case you can set up user groups and use the existing stars system to give more stars based on user count.
You can make a promotion task so it will happen automatically.