Picture tab
If an image and/or icon has been uploaded for the category, it will be displayed as a preview in this tab.
Thumbnail is the image that is displayed as a banner in the category view as soon as the category is accessed in the shop. Icon represents a subcategory in the category view.
The screenshot shows the "Kiteboarding" category with an image/thumbnail. For the "Kites", "Kiteboards", "Harnesses" and "Accessories" subcategories, their icon will be displayed.