Am able to select a new jpg and it shows that it has been recognised, but it wont upload the image on the home page. Was, however, able to upload it to general photo's. Pretty sure that the file is within the size constraints.
I use a Mac and was eventually able to fix the problem by closing their standard internet program 'Safari' and logging back in with 'Firefox' and down loaded it trouble free.
Interestingly, in Safari, I would select an image on the Mac and it would give me the option to 'Choose' only which only downloaded details of the image (i.e. IMG12345), but in Firefox, I was given the option to 'open' only, which completed the upgrade.