Image resolution reduced and files renamed when copying images to My Cloud

When I copy all my images from my laptop to My Cloud Drive over the local network, intially it looks fine, but after a few minutes the files all get renames and their resoution is reduced to thumbnail tiny resoltion. Why? I s there any way to keep my images at full reolustion on my icloud without zipping them lets say?

thanks

I’ve never heard of this happening – certainly doesn’t happen here.

What are they being renamed FROM and TO?

This has never happened to me. What OS are you using?