I love, love, love Kindle books and the iPad. Two great tastes that taste great together. However, the does seem to be a trend I've noticed with screenshot images in technical books. To be fair, this seems to be an issue from the publisher side of things, and not an endemic Kindle issue, as the Steve Jobs biography had wonderfully high-resolution images in the appendix to the book. Some publishers even do well with tech books.
But some publishers, perhaps under the assumption that the pics are just there to look pretty, crunch them all to hell so you can't tell what's going on. For instance, on this page in Real World Modo about the Shader Tree, the image, even in its zoomed, full-screen version, is simply too low-resolution to comprehend. I may have to actually pick up the dead tree version of this book, just so I can tell what the heck is going on.
Publishers, please get your heads out of your asses when it comes to digital books. I really want to go all-digital, I really do. I'd love to have my library in the palm of my hand. But crap like this, and prices for a few megabytes of bits that cost more than for Amazon to ship me a dead tree, are not helping your case. An ebook is still a book. Don't expect that just because I prefer information in digital form that I also prefer a sub-standard experience.