It probably shouldn't happen while you're in transit, but it could totally come up during a short rest.
I dont quite see how ...
Either you would need to return to camp for every short rest ... wich sounds both ridiculous and anoying.
Or you would risk stucking gale, or his mirror image in other obejcts ...
Also if you see it from purely RP perspective, it also does not make sence ... just imagine, you just finished fighting the goblins, decide to rest ... and sudently Gale instead of resting decide to spend his spellslot to summon his own mirror image so he can admire himself?
