Product images are not displayed normally, when I'm editing a product. It's like there's no data for the image or no image at all.
Please check these screenshots:
If I try to save product again, add another image or delete the existing one, I'm getting the following error
Notice: Undefined index: extension in /home/mywebsite/public_html/vendor/magento/framework/File/Uploader.php on line 602
which also points that there are no image data...
Weirdest thing in this issue, is that product image displays ok in product list:
Also, there are data about image in