Video clip thumnails problem

[efiste2]

I have ripped a couple of clips from my favourite DVD's and converted them using an excellent program called HANDBRAKE....However when i transfer these files into Itunes, NO THUMBNAIL shows up, and when I transfer the clips from Itunes to the Ipad2 a thumbnail does appear but its in a sort of coulured negative colour with a diaganol line through it......Has nayone else had this problem or does anyone know of a format which will show a thumbnail on the Ipad!!!