http://www.twogag.com/comics/2011-10-05-TGAG_052_Exorcism.jpg I think the first panel is unnecessary and the last panel is the most important.
Topic on Forum:Page Images
If the main issue is dimensions, why not simply change the orientation of the comic? (The full version is 339px wide.)
I do agree that your orientation is better for our purposes than the original (and I'll admit that at this point my editing skills are so bad I couldn't have done that myself without a little bit of trouble). I am not sure if the comic whole page is necessary. I definitely think it's useable without the first panel, but I am not sure how good of a trade off it is with space. I personally don't like it when a picture is so large it goes past the "examples of" box, which of course is determined by a number of factors (and I dislike it even more on Tv Tropes where it is more of an eyesore and where I developed the peeve).