To address these issues, we asked ourselves if we could create a visual impression of the image using only 200 bytes. Why 200 bytes? In order to remove that second network request, we needed to include some facsimile of the image itself in the initial network request.
one of the great strengths of web applications is that they aren't bound by the crusty old conventions of desktop applications. They're free to do things differently -- and hopefully better. Web applications should play to their strengths, instead of attempting to clone desktop applications.