Blake Shelton: Hard Boozing Tweets May Be Used Against You

Blake Shelton could be hoisted by his own liquor-drenched petard -- the magazine he's suing says Blake talks himself up as a heavy drinker, so he's got no place to bitch about its stories.

As we've reported, Blake is suing the publisher of In Touch for its cover story claiming he was rehab bound after hitting "Rock Bottom." Blake's filed docs denying most of the report, but in new legal docs ... In Touch says Blake must have forgotten the image he himself promoted.

The mag says Blake is famous for his "signature drunk tweets" such as, "Woah!! Almost 11:00 ... Can't believe I'm up so early ... This calls for a drink." In Touch says his tweets and comments cultivate his image as a "hard drinking country boy."

One part of the In Touch story says he partied hard last year in a Mexico hotel. Blake has denied staying at that hotel, but in the new docs ... In Touch says it has photo evidence.

Sources connected to Blake tell us the photo in question -- which was posted on Instagram -- shows him obliging a fan with a pic as he walked by the hotel.