1. Find a clip of something you want to make a small clip. I suggest using a vid that is a .mov file. I find these work best with Imageready.
I'm going to use a trailer from Tom Clancy's Splinter Cell 3: Chaos Theory.
2. Now in Imageready open the file. Now there will be a window prompting to to choose the range to import. I say you should only choose a scene thats around 5 secs. Use these settings for importing the file:
http://img23.exs.cx/my.php?loc=img23ℑ=giftut.jpg
3. Right now you have something like this size:
Now its time to resize your gif. Now go to Image> Image size. Now for the dimensions the max size for an avy on this forum is 100 x 100. Try to make it as close as possible to that.
4. Now its time to save what you have. Go to File>Save Optimized. Then save it whereever you want. Now your done.
This my finished product:
I know mine is alittle longer than I suggested, but its bigger than this board allows to be your avy. So better your make yours under 5 secs.
BTW I bet I have some typos in there, but too lazy to proofread.