Tonight I was browsing around Wikipedia in a semi-nostalgic manner. While committing said act, I saw a poor photograph of a particular and significant early-'70s motor vehicle that I rather liked when it was new. I downloaded a copy of the hi-res version of that photo, then cleaned it up in Photoshop.
Now I want to upload my enhanced version so as to replace the original, which is obviously heavily overexposed, and with too much red. Now how on earth do I do the uploading?
This is the existing Wiki file: