Something I think would make cel swapping much more efficient would be if rather than just swap drawing cels by the slider in your library panel, you could view all the cels as a full list of images and just click the one you want. Essentially something very similar to Keyframe Caddy/Frame Picker in Flash/Animate. I’ve found it a pain at times to have to drag the slider all the way through my list to check which cel I’m trying to swap to when being able to just click the image immediately for swapping would be great.
Take a look at the following post. The script works well and does what, I believe, you are asking for.
Thank you so much! This is exactly what I needed, it’s a life-saver.