[kh99]

I don't think you can use wildcards in REPLACE(). I'm not an SQL expert, but as far as I know there's no way to do a replacement like that in mySQL. You'd need to do a SELECT query, then do the replacement in php and update the row. You can use WHERE pagetext LIKE and use % in that pattern to select only the posts with images.

Also, the posts are cached, so to see the changes you'd need to delete the corresponding cached posts from the postparsed table, or if this is a one-time thing then you could just truncate that table when you're done the updates.