Adding/removing frames w/o changing number of handles

Hello

Ok let’s say I should encrease the duration of all selected segments(photos with a still duration defined during import) of the Timeline at once e.g. because needed to add handles(head and tail frames) for Dissolves.

For me, working with “physical” frames is easier than things like a timewarp effect.

Is there really no way to add(or in rare cases to remove) additional frames numerically, to all selected segments of the Timeline at once?

Thank’s a lot!

PS
Could this be a workaround for - at least - removing frames?
Increase the number of Tails and and choose consolidate handles?

Hoped this will be a possible solution: Set an In- and Out-point in the Src(green) (photos with a still duration defined during import) and insereted the selected source into the Timeline at the Positioner, with the yellow Insert Edit button.

Unfortunately this way the thing did end with 3 segments instead of one segement with more frames :frowning: