[theme-reviewers] Setting $content_width Dynamically

[Otto]

I've tried this sort of thing, and it is *fraught* with peril.

Make sure you test inserting content into various posts and pages and
such thoroughly. The content width is used on content insertion, not
just on content display.

Basically, the media uploader expects the content width to be set when
images are uploaded and resized. If you're only setting it on wp_head,
your results may be unexpected for various size values in the media
section.

-Otto