Hey Jarod,
The dotted bounding box is normal in firefox - it's the way that firefox distinguishes images for you when you click on one.
The blue / purple border around the images is the default link color and thus applied to images if they have a border. Images have the default border of 1 - to remove the border you must set the image border to 0. You can also change the border color.
When you use the back button in firefox to go back to a page firefox attempts to recreate the page as you last saw it in case their was in data that you need. For instance if you fill out a form and go to the next page and then hit the back button - Firefox will try and restore the text in fields. Generally this is not something done by the website but rather by the browsers ability to remember what you've done.
Hope this helps,
Abraham