I don't know a good upload service and used the first one google showed me. Do you know a bether one which u can recommend?
You could always have attached it directly to the post under the "Additional Options..." menu item when writing your post.
You might want to try Fritzing, It is a great breadboard centric layout system for creating electronic circuits. It can also be used for basic PCB design. It has a circuit diagram layout you can use as well. Best of all you can publish your fritzing files and other people can make suggestion and modifications directly to them.