Don't use all-caps in image descriptions!

Regardless of whether you're writing an image description for alt-text or a long image description that shall go into the post itself, do not use all-caps!

All-caps can irritate screen readers. They may not know whether it's normal text in all-caps which they'd read out loud as normal text, or whether it's one or several acronyms which they'd spell out letter by letter.^{1 2} So when you write, "ALL CAPS", some screen readers may correctly identify it as two words written in all-caps and pronounce it, "All caps." Other screen readers, on the other hand, may take it for two acronyms and pronounce it, "Ay ell ell see ay pee ess."

So even if you have to transcribe text that is in all-caps, you must make an exception from the rule that text must always be transcribed 100% verbatim. You must transcribe it without all-caps, but otherwise identical to the original, and mention before or after the transcript that this text or this part of the text is in all-caps.