Photoshop automatically changes the width of my image??

My problem is that when I open a short video in Photoshop that I made in Premiere Pro, it shows the image in the size that it should be, but when I click on image size, it stretches it in width. This is the same when I want to export it for web to make it into a gif.

On the left you see the image as it should be and how I opened it. On the right is the 'image size' option (alt, cmd, I). It clearly shows how the height is the same.

On the other screenshot you see the image as it should be on the bottom, and the 'image size' option above it. The width is not the same, but I didn't do anything to change that.

I have never had this problem before, and I can't remember doing anything different. Can someone please help me, this is extremely frustrating.