Why are my images distorted when view them in full view?

[Roberts69]

Hello all,

I hope you can help me with my images being distorted when looking at them full view (27" Apple iMac EMC 2639)

See the two images below... the one on the left is a clear image of a puppy and then, as soon as I click on it to expanse, the image just becomes distorted as shown on the right

I even tried a different viewer app with same result

 

[Slartibart]

Is this affecting all images or just a certain file type (PNG, JPG)? How does it look when you place it e.g. in a Pages document or drag&drop it into a Safari Window? Which version of MacOS?

 

[Roberts69]

All images. They are stored in the iCloud. The images work fine on iPad or MacBook laptop. Just my desktop (iMac 27" EMC 2639). The iMac has been factory reset with a fresh copy of Catalina with latest updates. Soon after logged into my iCloud, this is what happened.

I tried a different app to view my images and the distortion are still there. The thumbnails are perfect and clear. The distortion happened when click on an image to expanse.

Why would the images be okay on iPad or MacBook, but not on my iMac? Sound like an issue with settings? Tick boxes? Does 'Delete the imported photos' tick box have an effect on the images? Would changing 'Optimize Storage' to 'Download and Keep Originals' help?

 

[Slartibart]

First please try this.

 

[Roberts69]

Thank you for all your suggestions... I have noticed that jpg works, but not RAW format. Is there a plugin I'm suppose to install in order to get RAW format working?

 

[Slartibart]

So what RAWs are these? Which camera there are from? DNG? What bit depth?

 

[Roberts69]

Canon 5D mkii