Sorry, I do not have a surface tablet. I only have a Lenovo Miix 2 which is a 8 inch Tablet, currently updated and running windows 10.
I viewed your site using the Microsoft Edge browser. https://www.microsoft.com/en-us/windows/microsoft-edge
I do not see the images getting smaller and smaller until it’s not visible. I don’t think this is possible, there is no script doing such image re-sizing.
This is what I am seeing. http://share.pho.to/9g1ji/sj/original
The image posted for an article is of correct size.
This is what I am seeing for your homepage.
You set your homepage to use 3 column layout, the images will be small.
It will be even smaller, if you turn your tablet to portrait mode.
The only way is for you to set your layout probably to single column or two column, this will increase your image size.