The Photo data is the metadata embedded in a photo. Part of it is automatically generated when you take the photo (the so-called Exif data), other data is added by the processing applications afterwards (Iptc, XMP).
Show photo data
You can turn off displaying photo data here.
In the caption
You can choose to display the photo data directly on the info panel instead of the default popup window.
Show with label
Only the values or labels + values to be shown.
Reset to defaults
Easy way to reset the template to the skin's defaults. Can be useful also when you switch from Turtle, because Tiger's template is better.
Template
Give the required fields here. Those separated with pipes are alternatives, e.g. originalDate|Date/Time Original|Date/Time|CreateDate|ModifyDate and only the first found will be displayed.
Check your images in jAlbum with right-click → Extensions>List metadata for all the available metadata fields!