Changing Folder Images that you add to the dock

To me, your user name perfectly sums up the risk of messing with your Dock. There are all kinds of threads on this forum from (usually novice) users who run into big headaches from doing what you propose to do. If you were an expert user, you wouldn't be asking this, you'd know what to do and what not to do.

 

Check out CandyBar. It's not particularly cheap, but it does what you want, and Panic's a great company.

 

Here is a nice place to start to learn about this. There are apps available (not free IIRC) that will allow for quite a bit of customization. But all (edit: well, not all, but a lot) of it can be done for free with enough research and time.

Have fun! I spent hours upon hours playing around with this when I first switched from Windows to Mac.