Media Files open rotated images

I have a problem with media files opening rotated images. This is the page in question: https://www.athenslandtrust.org/affordable-housing/available-houses

Also note: although this page has image galleries, I had the same problem with individually posted images. The last image in the first gallery, as well as other images on the page, are all face up in their galleries, but when you open the media file, they are rotated to landscape orientation: https://www.athenslandtrust.org/wp-content/uploads/2015/03/dark-room-e1425477376929.jpg

The attachment page is correctly rotated: https://www.athenslandtrust.org/affordable-housing/available-houses/dark-room

The first thing I tried was deleting the image, making sure it was in the correct orientation on my hard drive, and then uploading it again. It didn’t work. Any other ideas?

Note: This is happening with other pictures on the page, but only the images that are supposed to be in portrait orientation. I.e. the media files are defaulting to landscape orientation for some reason. Please help!