Why is iTunes not showing all iPhone Apps to update?

Question

When checking for updates for my purchased apps in iTunes I sometimes have a few to download - no problem there.
My wife uses the same PC/iTunes but with her own Apple-ID. She can sign in and do the same. Every now and then there are available updates on both Apple-IDs which we can download and sync without any problem. All OK so far.
However, after downloading all available updates for both Apple-IDs and syncing to the iPhone, the App Store on the phone tells me there are more updates. As they are listed on the phone I can check the list against the Apps in iTunes (using get info) and sure enough there are updates available which iTunes does not tell me about. This means I have to update each one on the iPhone to get the updates instead of getting them all automatically using iTunes.
If I browse to an affected App in the iTunes App Store, the button beneath the icon shows as 'UPDATE' even though checking for updates does not identify it.
Using iTunes 10.6.0.40 on Windows Vista with iOS 5.1 on iPhone 4.

Answer 1

I've always assumed those silly strings were recording the results of the gapless playback analysis but whatever they're for it would be better if they were stored in a spare field.
Windows Media Player/Windows Explorer may be less fussy on embedded artwork formats than iTunes or the media file might actually be missing the art but the Windows Explorer cache (Thumbs.db) still shows it. You say removing-reimporting doesn't help but I assume you can still paste new artwork in and have it remembered. If so you might want to use the following tool to at least take some of the effort out of searching out which tracks you need to repair.
*How to find tracks without artwork*
To find all the tracks without artwork so that you can update them you can try http://www.stum.de/itunes-find-tracks-without-artwork/ for Windows or http://dougscripts.com/itunes/scripts/scripts13.php for Macs. Use Google, Amazon, Discogs etc. to locate relevant jpeg images. Ideally these should be square, 320x320 pixels or above and borderless to give the best results in the various menus. If you have artwork for some tracks of an album, but not others, select a track with artwork, right-click (Option-Click for Macs) on the art & click copy, then select all the tracks of the album, use CTRL-I or Command-I to *Get Info* and then paste the image into the artwork box.
I say 320x320 because I believe (from using TouchCopy) that it's the size used in the iPod cache so if you're going to crop or resize you might as well work to that size. Otherwise 200x200 is probably good enough.
tt2