Hello,
1/ You can use Lightshot screenshot or Gyazo tool to make screenshots and share links here.
2/ Please read this article – https://www.8theme.com/documentation/xstore/woocommerce/product-images/ It is recommended to use a graphics editor and prepare product or post images (make them the same size) before uploading images to your media gallery.
https://prnt.sc/mdo0RClvXB6F – you need to change the size of this image and optimize it, check APFEL KIWI product now – https://prnt.sc/0tDUCYLYIGzr
https://tinypng.com/
Regards