In an answer, I tried to use the spoiler markdown to hide an image. (It wasn't offensive, but it was unappetizing which seems worthy of hiding on Seasoned Advice.) But the image seems not to be hidden even if the text is. Here's an example:
This line is hidden... ...this image isn't! (This line added to show the problem is not a special case of this question.)
(Oh. Link descriptions aren't hidden either, it seems.)
Why is this?
In case this is browser-specific, I'm using Chrome.