AOk, so first read the below article.

http://money.cnn.com/magazines/fortune/fortune_archive/1997/12/29/235894/

Now I'm just curious, I've posted cakes on here that I've made that are obvious characters. I did so knowing that some images are copyrighted. If I stop making licensed characters today, what keeps them from coming after me for past cakes? Just curious what other people's thoughts are on this. :)

Nothing, other than taking the pictures down, as far as I am aware.

AThe statute of limitations for copyright infringement is 3 years, or 5 years for criminal infringement (e.g. for commercial gain). However one could argue that displaying an infringing cake is a separate infringement offense, in which case you would be safe from prosecution 3 years after all infringing pictures have been taken down (5 years if you have a business).

http://www.copyright.gov/title17/92chap5.html