Most, BUT NOT ALL, images place into my PCs iCloud for Windows Photos folder are uploaded, others never are!
I am using iCloud for Windows. I upload images to my i-Devices by placing those images in the folder C:\Users\your user name\Pictures\iCloud Photos\Photos.
Most images are uploaded without a problem, BUT some images never appear on my devices! Some of these images were originally taken with the iphone , some were taken with other cameras or were created with a scanner. So, what characteristics prevent images from being uploaded to iCloud photos? Or, in other words: What are the characteristics that an image must have to be successfully uploaded to iCloud Photos?
Note: I am using a fast computer with lots of memory and wifi with a fiber optic internet connection.