Your app might not display the image products due to certain factors. For instance, you might have added new extension(s) on your website or you may have customized a few attributes. If this is the case, your app will not display the product images because for every new product image, the resulting cache path is different from the default path, which is generally created by Magento. If you are not sure why the app is not displaying the images properly, write to us at firstname.lastname@example.org. We would need your CPanel details in order to check the cause behind this.