Dunkin’ Donuts has just cranked up its latest Twitter mini-marketing effort.

Through Friday, folks who tweet a photo of a lame lunchtime sandwich will have a chance to win a $50 gift card in what Dunkin’ is calling the “UpgraDDe Your Sandwich” Twitter Sweepstakes.

Sweepstake rules can be checked out by clicking onto this link.

The Canton-based chain may be best known for coffee and baked goods associated with breakfast. Presumably, this Twitter Sweepstakes looks to reinforce the message that Dunkin’ is about all-day hunger solutions, and not just breakfast, and that its sandwich menu makes for a good lunch option as well.

As noted in its press release, Dunkin’s bakery sandwich offerings include ham and cheese; a turkey, cheddar, and bacon combo; chicken salad, and tuna salad. Such items may be had on a variety of bread platforms such as French roll, bagel, croissant, or multigrain flatbread.

Dunkin’ Donuts has more than 10,000 restaurants in 32 countries worldwide. In 2011, those restaurants reported collective sales of $6.4 billion.