The scans, however, are not from the Reiner/CSO/RCA release but a Muti/Philadelphia/EMI release.That's really strange, blaaarg, I downloaded the files just now myself to check, as if I was just another user like you, and the covers came out just like the one in the OP above, from Reiner-Chicago.
http://i1243.photobucket.com/albums/gg548/dsphipps100/confused-1.gif
Is it possible that you might have (accidentally?) placed the Reiner-Chicago files in in the same folder as some Muti-Philadelphia files might have once been located? If you do this, then it's possible that WinAmp, seeing the similar location for the playback files, might dredge up some old coverart from a previous Muti-Philadelphia version (which I did uploaded here about 6-7 months ago), making it look as if it's meant to go with the present Reiner-Chicago files. Try moving the Reiner files (including the accompanying "cover.jpg" file) into a different folder with WinAmp or whatever your media player is, and see if that changes it. Let me know if that fixes it for you.
https://dl.dropboxusercontent.com/u/42753709/Photobucket/nod.gif