We need help creating a user and backend friendly gallery page

General information for the website: We sell flooring
Kind of development: Customization of existing website
Description of requirements/features: We have a new beta site that we're going to move out into production, but we need to create a better Gallery page. We need to be able to let the user filter all of the pictures, by giving them a dropdown list to select the color they want to see. Some users are only interested in certain colors.

On the backend, we need the ability to upload the pictures and tag them with what color they are. Then, on the Gallery page, the user should be able to select the color they want to see from a dropdown list, and selecting the color will then filter the results.

Here's the current beta site gallery page: http://tinyurl.com/plnvqwx

We have an admin page on the backend where we can upload pictures (see attached screenshot). The problem is, when we upload them we don't currently have a way of specifying their color, so that the user can use the drop down filter.

Can you improve this backend upload process and user experience for us? Let me know your thoughts.
CMS and Admin requirements: Once we select a developer we will pass along the login info
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