The BBOS version on the 7210 device is 22.214.171.124, with the 7700 device the OS version is 126.96.36.199. NOTE, these are color devices. On a black and white device(6200), an ODD width image with text is NOT an issue.
My initial thought was to do as you suggestted, always create EVEN width images. But that implies that createImage works half the time.
I posted the same query on RIM developer forums, so far no one can answere it. I will report this bug directly to RIM and see what they have to say.