Well, those are indeed the toppings you'll see at your McDonald's, Burger King, Wendy's, etc, but I'm of the opinion that pretty much anything foodwise is potentially
a burger topping.
20 years ago you'd never see mushrooms or blue cheese on a burger, today it's everywhere.
Anymore, unless I know I don't like the topping by itself - like bleu cheese, for example - I'll try it on a burger once.
One thing I recently tried: Steak n Shake offers a breakfast sandwich that is in essence a steakburger with cheese topped with a fried egg. Really, this is quite good.
On the matter of posting pics: the pic has to be accessible already via the internet, and then all you do is post it between two image tags, as explained in the link on this page (hunt for it, hehe) that says "Forum Code
is on". You can't upload\paste an image to use on this site.
1) Find a pic on a web page that you want to post.
Example: there's a nice pic of a steak dinner at Doe's Place on the main page of this site today.
2) Get the url for the pic (right click, properties)
In this case, the url is http://www.roadfood.com/photos/mini_3245.jpg
3) Create a post with this url imbedded inside img tags
4) Here's what the resulting post will show