Yoast and Estore thumbnail uplaod button MIA

I am using estore and SEO Yoast and am working on a site I bought via Flippa - I am fairly new to the Ecommerce world -

I added a post mimicking what teh origianl owner did everything seemed to word fine (aff codes) but when it came to uploading a thumbnail teh upload button was MIA was there before as i changed a thumbnail pic on an image the original owner - I tried to insert teh url of the image from my media library still nada - I have been reading an looking at youtube videos and the upload button is there? Any ideas would be appreciated