pros - useful against hot/direct image linking - can control browser cache - can protect images with coldlinking/watermarks - can generate/manage thumbnails/effects directly from the server end
cons - harder to develop/manage - may backfire against spiders who cache/crawl images - SEO
also you having a full url for the image like you posted may create complications for non-secure/secure pages as the same image may appear for both page types. Best to use a relative path.
