How to select multiple images with activity starter?

the built in activity starter is not able to work with boolean values…
you might want to try the Activity Starter Extension by pepemont, which additionally is able to pass boolean and long values

read the short documentation about how to use it

Any key starting with “B.” or “l.” will be passed as boolean or long respectively.

see also this thread

Taifun

PS: a link to those threads might have helped to not again repeat what already has been said elsewhere