Lil Scrappy ARRESTED in Atlanta -- Photos Inside

Rapper Lil Scrappy -- the guy behind the 2006 hit "Money in the Bank" -- was arrested in Atlanta, Georgia earlier today for violating his probation ... TMZ has learned.

TMZ obtained photos of the 28-year-old rapper being taken into custody on the side of the road ... where he was handcuffed.

Scrappy -- real name Darryl Kevin Richardson II -- was booked at the DeKalb County Jail.

According to his booking sheet, he was listed at 5'10" and 185 lbs.

It's unclear why Scrappy was on probation in the first place.

Story developing ...