Merge duplicate GIF frames in Photoshop

Question

I'm trying to optimize an animated GIF size. I read that one technique is to reduce duplicate frames (still frames with no movement) to one, and combining their time.

So for instance, in my animation, from image 12 to image 33 there is no movement, I shift select frames 12-33, but I don't find the merge button, is there any?

What it should do is combine frames 12-33 into a single one, and add their respective time (instead of me doing it manually, because there will be more than one still moment in the animation...), which in this case, where every image has a 0.3s duration, should create a combined image with a (33 - 12 + 1) * 0.03 = 0.6 seconds duration.

Answer 1

I dont' think there is a merge function. If the image doesn't change between frames 12-33 I would: select frames 13-33, delete them, then change the time on frame 12 to be the total time of frames 12-33.