Spammers are a crafty bunch, using a variety of techniques to spread their unwanted junk. One way they do this is by submitting comments to the special pages WordPress creates for each image that has been uploaded. Spammers find these pages and submit spam. But there are ways to thwart their misdeeds!
Lately we’ve been using the Redirect Attachment Pages plugin, if the client does not have it available through an SEO plugin.