Default Galaxy S3 mini photos aspect ratio problem

When I view my photos in gallery in landscape view, they usually fill the screen but recently the aspect ratio seems to have changed
and the photos no longer fill screen with 2 black bars each side of photo. I have never changed any settings to cause this
and i cant find any camera or photos setting to fix it. I have attached a picture.
Attached Images
File Type: jpg Phone picture.jpg - [Click for QR Code] (40.9 KB, 17 views)