Can't add images to existing item

[kamorgan]

I am trying to add more images to my listing. I go through all the steps. To revise a listing, go to My eBay > Active Selling. Find the listing you'd like to revise, then from the More actions drop-down menu, select Revise. Make your changes to the listing, then select Revise it. 

When I reach the revise it page the listing shows  the images and the 12 boxes on the side to add images. Problem is when I click on the boxes to add another image it doesn't work. No box can  be selected. I tried another browser (Internet Explorer) and you can click a box  with it either. The main picture shows on the left and I have 2 other pictures to the right side of it. The rest of the boxes (10) are blank , when I click on them nothing happens so I can add more images.

Any help appreciated thank you