Google products are becoming more integrated. Now you can integrate Google Analytics in Picasa Web Albums, so you can observe the number of visits to your photos.
View this page for more information….. Using Google Analytics to track visits : Captions, Comments, and Tags – Picasa Help.
Google Analytics is used by webmasters and bloggers to observe readers traffic flow (visit, view, hit) and the results were analyzed for to be optimized further. Optimization steps are often also called SEO which stands for Search Engine Optimation. Search engine are usually the biggest referrer of a website or blog.
If your website or blog is well optimized, then you can make money from there…..