on the ones with red x's are you able to right click and select "show picture" or something like that? if so, are you then able to view the pic?
another idea- In Ie's "Tools"menu, click "Internet Options", then click the "Advanced" tab. Make sure the "Show Pictures" check box is checked under "Multimedia", and click "OK".
Yeah, a lot of sites like (imageshack,photobucket, webshots flickr, etc) have bandwidth limits - so if the user who posted it has exceeded ther limit their pictures are disabled... or if their server is too busy you can't see the pictures.