Image Distortion since recent update

Since the recent WordPress update, images that I upload into the Media Library are behaving differently to images I uploaded prior to the update.

1. When you preview the image in the Media Library there is no thumbnail available, where previously there was a thumbnail.
2. When I insert an image uploaded after the update into a photo gallery in my ‘Photo Gallery by Supsystic’ plugin, the image is distorted. Any images uploaded into the plugin prior to the update display without distortion.
3. When I just insert images into a page there is no distortion of either image.

Question – Has something changed in the formatting of images that are being uploaded into the Media Library? and has the thumbnail feature been removed? also Is this causing an incompatibility with the ‘Photo Gallery by Supsystic’ plugin?

On the link provided, you will see examples of images uploaded before and after the update and how they behave on the page and in the gallery.

Thank you!

The page I need help with: [log in to see the link]