This confirms that bikes are in the upcoming GTA, as they were noticeably absent from IV. Teasingly Rockstar's Newswire ended the update saying there's "more to come this week..."
We've already received two still shots of the game with a guy sitting by a lake, and of a police helicopter hovering over Los Santos. This takes the count up to a total of five.
The avid GTA community note that the official GTA V website has been updated with the screenshots but that three spaces remain empty, possibly signalling that at least three more images will be released later this week. The new images are posted below for your viewing pleasure. No platform or release date is yet confirmed for GTA V.