whitespace inserted into home page

Enabling the img_assist module inserts a block of whitespace into my home page between the first article and the "more" link, extending to the bottom of all sidebar blocks. In other words, further content does not begin until below the last sidebar content. Disabling the module removes the whitespace.

I am using a customized version of Andreas09 theme (with fancy theme elements), but this problem was unaffected by any style changes.

Effect occurs in Safari browser (OSX) but not Camino/Firefox. IE browser in OSX inserts whitespace :before: first post, again to the bottom of all sidebar content.