No tool for that.
You will have to select everything in the timeline area to resize but this might mess up your transitions.
You can also resize each element by multiplying Width for example by .75 (for 75% of original. Make sure your playhead is a 0.
Yeah, I have tried selecting everything and it does just that. Rats.
Hi, Something to help you out of the experience I recently had in 2 projects. But also with the Help from 'resdesign' they turned out Fantastic. What I learned, if you 'Turn Off' the 2 Icons in your Timeline just next to the 'Pin' (Yellow and Blue icon) You can resize anything carefully just like using Illustrator by holding the 3 keys down (command, opt and Shift) before you grab the handles with your cursor and size your objects. When you run the Play button your Objects are sized. You also have to place your Timeline just before and after your transitions to make sure you get the begin and End sequence.
so for example if you have a Logo that becomes from 100 px to 25 px and moving to the Left and your Stage now is going to change from a 300x250 px to a 728x90px project. Carefully First Turn off the 2 icons then place your timeline (redline) before the Logo start to get smaller from 100px. If its gone off stage just select the logo from the List in the Timeline Panels (layers) then you can select it. If you still cant get to it then LOCK all the layers till you can select it and then do the re-size. Then move your Timeline to the part that the logo gets smaller and you can scale it again. If your Elements are just gone off screen then use the first method but make sure you turn off the 2 icons before that and carefully one-by-one do this for all elements and save as you keep advancing and Testing 'Play'
With practice this works Well and I have managed to change 2 web banner campaigns in this method in various sizes and using just one size as a master. These banners were complex using animation and text transitions.
hope this was helpful