Creating the Gallery prefab

When it runs, our project will house multiple images in individual galleries. Each gallery will be a self-contained prefab containing thumbnail previews, scripts for user interaction, and a category title. The next several steps will involve building the first gallery. Once completed, these objects will become prefabs for creating additional image galleries with their own unique content:

1. Make an empty GameObject and title it GalleryHolder.
   This object is the primary receptacle for the individual galleries. All images and canvases will exist inside of this container.
2. Move GalleryHolder to (0,0,0).

3. Add a Canvas to the GalleryHolder GameObject and name it Gallery.
   Do this by right-clicking on GalleryHolder in the Hierarchy window and choosing UI | Canvas.
4. Rename the Canvas GameObject Gallery in the Inspector.

This canvas will be the parent of the individual...