The picture comes up fine - it's a bit cropped on my phone but can be swiped sideways to see the rest (which is good - most photo upload sites will resize it for you but don't work with swiping across). It's probably a good size on a computer, depends on the screen size though. You can resize it before you upload to the forum, or use a free picture upload site like Tinypic.com to resize and host it for you)
Saved image on iPhone, screenshotted, crop in Photos, edit in Photo Studio app, saved back to Photos, upload as attachment Still a bit big, should have screen shotted the original in portrait mode before cropping