Can an electric dryer be vented into a garage?
Dryer air is hot, but more importantly, it is very moist.  The high humidity might not be a huge issue when it's cold outside, but when it warms up, it could lead to mold or other moisture related issues.  Also, even though your dryer does attempt to catch lint on its internal lint screen, some dust is present in the exhaust air which will eventually cause a mess in the garage.