flickr versus picasaweb

A posted some pictures on Flickr, and seeing the slideshow was a waiting experience: "Loading...." Something of a contrast with the slideshows on Google photos - Picasa web albums. Checked with ethereal. Found that pix used by Flickr are 300 kB average size per pic, while Google's pix are one-third the size. Bandwidth usage for Flickr slideshow at 1 second per pic was touching 1 Mbps easily and still managed to show the "loading" progress bar on occasion.