im sorry if this is redundant

i looked in the memories and didnt really find anything. i want to make an icon from a movie, but i want the whole thing to be the movie, not just have the movie on top of a base picture. i have virtual dub so i selected the bit i wanted, but its still the normal size, and i dont know how to resize it to 100x100 without going frame by frame. i tried doing it in ulead gif animator, but i didnt really have instructions to use it and it wasnt working. so id be eternally grateful if someone could help me. i can download any program it takes.