I think you can still purchase it -- I mean, it's still being published -- so maybe there's some reason why only the text seems available online?
I found a website that 19th century schoolbooks on it, looks like quite a few. So far, everything I have looked at is scanned page-by-page, which I personally find only slightly less annoying than having no pics at all. I haven't seen the McGuffey's on here yet, though.Here
is a link to their Browse books section.
ETA: I posted too soon. Here
is a link to a page that lists the McGuffey's readers, and so far, all scanned page by page. Not always great quality, but it's all there.
I pasted a page into microsoft word, and it actually fits quite nicely onto one page, though I can make it a bit bigger without going off the page. Either way, since it's scanned, it's not crisp and clear like typed text -- kind of greyish around the edge of each letter. I'm not sure how easy a read it would be. Maybe text capturing software would work -- I wonder if my dh wants a computer stuff project to take on
I found the readers through a link on this website