Images In Description
If your description that you use for OpenCart contains images, you need to ensure that the URL's for the images point to a full web address.
For example if you have an image source like: src="./images/myimage.jpg"
This needs to be changed to a full web address like: src="https://www.mystore.com/images/myimage.jpg"
This is easily done. Go to the product page in your shop as though you are a customer viewing your website. Right click on the image and (depending on your browser) view the image - it should then show you the image on its own for you to be able to copy the web address in the browser address bar. Some browsers may also allow you to "copy image location" when you right click.
You then need to update your OpenCart description area for this image and change its source (in the img tag it is called src) - to this new address.