Doc, that is the icon for Adobe Reader, not a pdf file.

@ Daiwa:  Adobe plays by their own rules, OD has fits trying to display thumbs too. May just be stuck with the default icon. Sorry I can't be more helpful but I gave up on using IP due to its many issues.

That's the one, Doc. By "overlay" I think he means the red rectangle with PDF on it. As I said, Adobe seems to have their own mindset regarding how their property is displayed. That may be something that cannot be easily changed.

I'm currently without an image repository or I'd upload a snap.  (Only have an image suppository at the moment so am limited to downloading crap.    That's poetry there, son.)

Best description I can give is to have you imagine that two different icons are associated with the .pdf file extension: the 'default' (generic) icon from the icon package, and Adobe's .pdf icon.  The Adobe icon renders at about 25% of the size of the default icon and is centered 'in front' of the default icon.  Big icon in back, little icon in front.

I still like IP & use it despite its idiosyncrasies.  This is more an intellectual puzzle-solving exercise than anything really important.  I can live with it the way it is but would enjoy finding a way to defeat the glitch & put another notch on the handle of my skinning blade, so thanks to all of you for chiming in and being of help.

OK...so it's a matter of 2 icons being used at once, one 'on top' of the other (actually simultaneously). 

Did you try asking the guys in Support? I've never heard of this one, and only for Adobe. It's as if IP is calling on both and ignoring instructions.

Did this problem occur after installing an Adobe update? Seems to me, it's probably Adobe pdf reader and not IP. But I'd definitely ask the guys, Daiwa. Good luck with the image suppository...those corners must really smart.