Dryers get vented into basements and garages all the time in the Midwest (don't know where you are). It's not the ideal situation, but it's not going to kill anybody. If its just the lint factor you are worried about in the garage, you can cover the end of the vent hose oulet with a single knee-high panty hose. Usually a large rubber band will hold it on just fine. This will trap the smaller particles of lint, and is easily changed out as it gets full.
Unless your garage is EXCEPTIONALLY well insulated, it's probably got enough draftiness to offset any moisture content from the dryer air.
Also, you can vent up through the roof. Also not ideal, but doable.
Personally, if I had the choice, I'd use the garage connection. Besides, it makes your whole garage smell like fabric softener... not a bad deal!