P: Ability to change the duration of multiple layers at once

Not sure if anyone answered your question. While there doesn't seem to be a straightforward solution to this which is so bizarre, you CAN select them all, move the playhead or current time indicator to where you want to split all the layers and then using the scissors tool, split them all from the same location. This will divide all the layers for you into two sections. The section with the correct length and the excess is in a separate layer for each original layer. You can go ahead and select the excess part from all the layers at the same time and delete. Then, rearrange or stack the now-trimmed layers however you want. Make sure when you want to split them that they are all starting at the very beginning of the timeline so you are trimming them all correctly, so ideally you do this step first thing then you rearrange. Hope that helps and let me know if you need screenshots to share this

Oh you have saved me from yet another infuriating gif creation session having to adjust a zillion layers and stagger them. Awesome. Thank you very much indeed for this, it is much appreciated.

Oh!!! It's been 3h that I'm looking everywhere on the internet for THAT especially.

THANK YOU SO MUCH, it work very well. I was desperate to move timeline after timeline. You're a game changer. I'm gonna save so much time.

Bless you! 

I can't believe that the discussion is running since 2017... and Adobe is doing nothing. It's an important options in photoshop.

omg it is such a game changer! thank you!!

Hi Horshack - awesome script - saved me a bunch of time.

Thanks so much!

this is a wonderful script Horshack, ive been using it for ages. but it doesnt seem to run on the laterst version of photoshop.

can anyone suggest what code needs to change to make this work please

thanks

Thanks! This worked perfect.

Really great work, thank you!

There is an incomparably better way. Check out Clip Studio Paint. The program has a normal, ergonomically designed timeline. In addition, in this program you can draw by hand with vector brushes that look like raster. the End result doesn't look like flash but like photoshop. Another solution is Krita or TVPaint. Unfortunately Photoshop is the worst program I have encountered when it comes to frame-by-frame animation. I wonder why they made this timeline so clunky and didn't even give buttons for basic functions like onion skin. Instead you have to dig through the menu.