Well, the pin behaviour is the best bet for this purpose, but you first need to set its position, then pin it (both in the event sheet), for best results (in this case, at least). Unpinning can be done in the event sheet as well.
Your other option, which is functionally the same as using the pin behaviour, is to set position to another object each tick, specifying the desired image point. This way you can specify another condition, maybe a timer, and when that other condition is no longer met, the child object will simply cease to be "carried".Here's a quick example
(r134). Drag the green block onto the pink one.