I've never tried the generic stock stuff you find online because it seemed to low of a return on effort.
You're quite right for the majortiy of stock sites - many only paying pennies for your works of art. I hunted hard to find online equivalents of the traditional image libraries that not only accepted my relatively low res digital shots (Nikon D70s producing 6Mp RAWs) and also scans but more crucially, I wanted a library where I had control over how my shot were used, i.e. Rights Managed or Royality Free. I was not interested, at all, in the sites that accept all your images, sell them to IKEA for production into posters generating tens of thousands, and only paying you $1!!
So my options (at the time) where the US based 'Digital Rail Road' (which I subscribed to but it went bust) and so more recently the UK based 'The Image File'. I find The Image File to be suberb - excellent customer support, great marketting tools, and they do not ban your images just because you're not using the latest DSLR, and I can submit my scans to them. As stated above, I bet Getty USED to accept The Canon 400D 10Mp camera a couple of years ago, but now they probably don't because it's the 'latest' model. It's a daft restriction in my view - my D70s produced superb prints from RAW up to A0 and similar.
Anyway, some interesting views here.