Your picture file size is too large. If you reduce the size to no more than 1200 pixels for the largest dimension your picture will post in the orientation you want it to. I resized your first picture as an example. And with most basic photo editing software you can crop the picture as shown in the second picture.
Like Smokey said, hold your cell phone horizontally and the picture will post upright when you do your post. If you hold your phone vertically when you take the pic, then when you post it, it's going to post sideways. Took me a while to figure that one out also. Nice old padlock.