Jumpy images in file managers

[celticmagick]

For some reason my images are jumpy when viewing them with a file manager. I first noticed this when I clicked to view a screenshot with the Files app. I checked other images and had the same result - file format doesn't have any impact, they're all jumpy. Thinking it was the app itself I installed a 3rd party file manager and had the same result. If I view the images in Google's Photos app they appear normal and without any distortion or problem.

Anyone else having this issue? What could be causing this and to only affect viewing in a file manager?