That's one of the nice things about the wiki several people can work on the same project. I don't fully understand most of it, but it's fun playing!
Don't worry about the coordinates, I'll happily take care of that bit. It just gives the facility to put several links within a diagram, that way we can take your schematic and make each component link to the pertinent wiki page.
You up load a photo or graphic thus ...
Give the file a suitable and descriptive name and make it no bigger than 2Mb, log in, click the “Upload file” link in the "tool box" in the side menu and simply follow the instructions, it's no more difficult than putting a photo on ebay.
If you still have problems you are welcome to email them to me and I'll re-size if necessary and up-load for you. In fact, if we are going to link components on the schematics, email them to me anyway and I'll sus out the coordinates bit before up loading. julian (at) palmergroup dot co dot uk.
Let me know what the page is about I'll start the page/pages off for you.