Thanks for posting your question here. In order to make the item you have removed from your scrolling gallery show up there once again, you will want to mouse over the Stores tab within your account, select the "Manage Items" option under Emporium(on eBay), and then click the "Show Hidden Items" button near the top of the ensuing page.
From there, you should be able to make the desired item visible once again by checking the box next to it and clicking the "Make Visible" option. Once you have made the item visible once again, it should have the potential to show up in your scrolling gallery the next time it refreshes, which happens automatically every 2 to 4 hours.
I hope this helps. If you need any further assistance with your account, please feel free to contact our customer support team by mousing over the “Help” tab within your account and selecting the “File Support Case” option.