Not entirely true. My blind friend encourages me to annotate screenshots whenever possible. It's just a pain, because you have to remember to do it as you tweet (you can't do it later), and only you can do it (why not crowdsource it?)

Can screen readers still not read text in images? Years ago I could understand that being a problem, but now? If that's still true then it seems to me those screen readers could really use an upgrade. My phone has been able to copy text out of screenshots flawlessly for years.

I do agree with the overall point though that images are a suboptimal way of conveying text.