Blackmoor Vituperative

I have a number of web sites I administer. Most of these are hosted on Dreamhost, and most of them run MediaWiki.

Recently, I have noticed an error whenever I upload an image to the wikis. What is supposed to happen is that ImageMagick resizes the image to make a set of thumbnails. What has been happening is that ImageMagick displays an error:

Error creating thumnail:

Exactly like that, with nothing after the colon. After many hours of research (and great help from the Dreamhost tech support team), I finally found the solution. Add this line to the LocalSettings.php file:

$wgMaxShellMemory = 524288