Problem with Photo Resolution

[blacan9]

I started having trouble uploading photos into my ebay listings yesterday. For two years now, I have been using an I-phone to take pictures, then saving them to my computer. Then I upload them to ebay. No issue until now. Yesterday, all of a sudden, I started getting this message;

"Photo quality issues

Upload high-resolution photos that are at least 500 pixels on the longest side. If you're uploading a photo from your smartphone, select the Medium or Large photo size option."

I am aware of photo resolution requirements, but up until now, my photos were fine. Since I had an old I-phone, I went out today and purchased a new one. To my horror, I am getting the same message about photo resolution.  

Can someone help? I don't have a clue why this is happening.