Context: currently, the Google Docs Viewer/Embedder, when used to display a PDF in a browser, heavily downsamples images in the PDF resulting in grisly color changes and posterization. This has been discussed for a long time elsewhere on the web (example) and is something Google might eventually deal with.
I assume Google's intention was to hack down bandwidth usage, which I don't begrudge them, but the results stand out glaringly in an otherwise vibrant WWW. Embedded fonts work fine, and the only other visual/layout errors can be with some more advanced design effects—unless they are flattened down to Acrobat 5 compatibility.
With the nasty color changes, what I believe I'm seeing is a re-processing of the images in the PDF with ye olde web-safe color palette. Or maybe its paleolithic predecessor. FYI the source PDF is unaffected. And FYI, yes, I am aware of many other options for embedding a PDF in a web page; I'd like to try and solve this one.
My thinking is this: if I can output my InDesign file such that images are converted more gracefully to a web-safe palette, and possibly with more satisfactory color dithering, then the results via the Google Docs Viewer/Embedder might be improved, more predictable, good enough for now.
I know how to do this with Photoshop, and I assume it's a Photoshop engine working behind the scenes in/for InDesign when processing images, so I'm hoping this is attainable.
Thanks in advance for any creative thinking.
Edit: it's looking like the limit is far fewer colors, possibly 16. Gross. But I'm still curious about the possibility of a method for this, as it could have other applications.