Google Image Search started to index images uploaded to Blogger in December 2007. Until this month, all the images were prevented from being indexed by search engines for unknown reasons. This move is closely related to the fact that the images hosted at Picasa Web Albums started to be indexed by Google.
The images uploaded from Blogger's interface are hosted at Picasa Web Albums, but they're also available at subdomains like bpX.blogger.com, where X is a digit. Another Blogger oddity, inherited from Picasa Web, is that you can't directly link to an image.
Images uploaded before August last year, when Blogger launched the latest major upgrade, are still not crawlable.Google, Blogger, Images, Image Search, Image Indexing, Crawling, Google Bot