I use Photoshop and it’s quite an old version. Nothing special. Well, I don’t know well how to use Imageready so I’ll try to explain with Photoshop. Is Imageready similar to it, or a part of it? I don’t remember now. Anyway, to make a gif size small, I make a layer for the unmoving background.
This is my gif. Look closer, and you can see the curtains, the door and the pillow don’t move at all. They don’t have to move, the only thing in the gif moves is Benedict’s body(oh yeah) and the letter. So make a layer with unmoving part of the picture like this.
The place where Benedict is has to be transparent. And put this layer on top of other layers like this. The layer covers the non-Benedict parts of the other layers.
Less moving parts means smaller size. But you know, you can use this unmoving layer only when the entire frames are the same angle.
Sorry, my English is not so fluent that I’m afraid you might have trouble to understand what I want to say. But I really hope this could help. And you know, this is not my own unique thing, it’s being used by almost every gif makers. :)