The roundtrip latency means the server will send more packets than you really need, and it&#x27;ll have read more data off disk than it actually sends.  The client has all the information about dpi up front, so it has the ability to make a precisely described request up front.  Also, you&#x27;d have to make your images be JPEGs, and use tools that generate the kind you need.<p>I also don&#x27;t see what complexity you see.  Instead of specifying one URL, you specify a small family of them.  That&#x27;s not architecturally more complicated -- it&#x27;s a change of datatype.  The behavior&#x27;s straightforward and the presence of multiple versions of images is highly visible, instead of being a detail of some binary file.