Establish which image was clicked on
Establish which image was clicked on

By using this incredibly esoteric, data-id thingy we can pass
information between the DOM and the JS. Maaaan! This was difficult to
track down. I know I'm just missing some basic HTML5 concepts, but dag.

scimusmn/sd-scrapbook,scimusmn/sd-scrapbook,scimusmn/sd-scrapbook