I had accommodated your request to replace Savannah's image with my modified one, but I'd forgotten to post back here that I did so - sorry. So unless you've changed it, the one you now see on her posts should be the one I reduced.
As for dimensions... Your original debut image was at 800 x 479. I took that one and reduced it to 418 x 250. Both sets of dimensions have an aspect ratio of 1.67.