Anyone using Magento 1.x or have developed eCommerce sites with Magento 1.x would be facing issue with the image upload problems on new browser versions, Chrome, Firefox and Edge. Adobe is deprecating use of flash on internet browsers by late 2020.
To solve this problem you need to upload an Magento HTML 5 image uploader. You can get this here: https://marketplace.magento.com/mavenecommerce-html5-uploader.html. If this is no longer available on Magento marketplace go directly to developer here: https://www.mavenecommerce.com/2016/10/18/magento-html5-uploader/
Or manually download and upload the extension to your Magneto site.