What context and what does that mean exactly? Image processing is not usually a difficult hurdle.
As pier25 suggested, I was thinking about imgix. We (a marketplace) stopped using our hand-rolled image processing service for Imgix, and now enjoy their performance and suite of clever tricks to deliver the least bytes the fastest to the user. The impact on SEO and conversion is non-negligible.
Interesting. You mean something more advanced than you can do with some command-line scripting?