There is no text parameter on a link object. You must be talking about the "text" Shadowbox option. This does not define text that will display under an image. Instead, it defines textual messages that will be shown to the user when errors happen. It is provided for i18n support.
Your animation while opening and resizing an image is most attractive and having the "title" at the top of the image is elegant!
Is there a possibility that you will be adding an additional text area below the image as well? As near as I can tell, there can only be one line of text at the top--additional lines seem to go underneath the image. This is a bit limiting for the use I have in mind.