A few months back we started removing the srcset attribute from images on the mobile interface as a bandwidth optimization.
This is probably OK for photos, which usually look only slightly fuzzy on a 1.5x, 2x, or higher resolution mobile screen, but makes diagrams rendered from SVGs look very fuzzy. I cannot currently attach screenshots from my iPad as phab requires drag and drop. :)
We should either not remove the srcset attributes for such diagrams, or we should go ahead and pull the SVG directly if it's suitably sized.
Probably other tasks to ping on this, but I'm on slow network right now and it will take a bit to track them all down in phabricator. :)