different episodes artwork to tv programme artwork

[rswatkins]

Firstly thanks to everyone who have posted and replied, these forums have taught me a lot since I got an ipod touch. I am stuck now though. I have managed to get my tv programmes to display properly on my ipod, I have changed the artwork so each show has its own artwork, and when I enter into a tv show I can get a different artwork to display for some episodes. but then sometimes when I add a new episode the ipod will change the artwork for the tv show. The shows and episodes I am using are all custom videos, I have manually entered the meta data / get info tabs. There does not seem like any reason why it would do this, ie I thought it may work on first episode put on ipod, or alphabetical order of file name or show name etc. but it seems just random. So my question is what are the rules ipod or itunes use to display different artwork for series and episodes. Sorry if this has been covered before but I have not been able to find any info on this. Thanks in advance, Roy