Using a ruler I make the sides to be proportionately 92 to 127, so
width 1500 x (127 / 92) gets a height of 2070

which is [-img width=1500 height=2070]http://i.imgur.com/fnmIRO7h.jpg[-/img] without the two '-'s.
Which doesn't work.
So tried doubling the now coded sizes to 724 and 1000...

Hmm.
It auto corrects to the preset size now. But didn't the first time. Hmm.
[edit] Doesn't work whatever I do now.
[edit] Works now - as proved by second attempt above. Thanks Mids.