I experienced that years ago when trying to upload directly from any "i" device to a forum. The resolution I found was to go the extra step and first upload it to a hosting service like imgur, etc. Believe it had something to do with format interoperability w/ assorted forums. Same bs applies when an "i" image is uploaded to forums, attached to emails, etc and when eventually observed by a recipient, it's rotated. Don't get me wrong, I like Apple quality but loathe their obsession with control and the reasons behind the two examples cited here.
I've posted many pictures on this site in the past. I use Photobucket, I go there and copy the link then hit the picture icon on post reply page and as soon as I tap the icon Safari crashes and closes the page.