UberCart product image won't scale
May be the css property for the image in the full page was written as width:100% and height:auto , so it will always makes an image in large full size. you can check by inspect element to see the correct path of image style is coming or not.

You can get the image path from there and paste that in new tab to see what size of image is coming without applying any css rules.

Hope this will help you.