snap to

snap to (attention)

1. To suddenly or abruptly begin paying attention. I was lost in a daydream, but I snapped to when the teacher called my name. The kids snapped to attention when I slammed the ladle down on the kitchen table.
2. To quickly assume military attention. You become trained to snap to attention when a superior officer enters the room.
See also: snap
Farlex Dictionary of Idioms.

snap to (attention)

Fig. to move quickly to military attention. The troops snapped to attention when they saw the general appear. snap to when I tell you!
See also: snap
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

snap to

Move swiftly and smartly to an action, as in The troops snapped to attention. This phrase is sometimes expanded to snap to it, as in You'd better snap to it if we're going to finish today. [Early 1900s]
See also: snap
The American Heritage® Dictionary of Idioms by Christine Ammer.

snap to

v.
To pay attention or begin complying suddenly: The troops snapped to attention when the general appeared.
See also: snap
The American Heritage® Dictionary of Phrasal Verbs.

snap to

verb
See snap to attention
See also: snap
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • snap to (attention)
  • snap to attention
  • grip (one's) attention
  • attention
  • get (one's) attention
  • turn (one's) mind to (something)
  • call (one) to attention
  • call to attention
  • hold (one's) attention
  • hold attention
References in periodicals archive
A few days later, Citi analyst Mark May downgraded Snap to Sell arguing that the flagship app redesign could produce positive long-term benefits, but the "significant jump" in negative app reviews since the redesign could result in a decline in users and user engagement, and could negatively impact financial results.
That was worrying for investors who have been pressuring Snap to roll out a new Android app that will fix a host of problems from lag issues while scrolling, to random crashes, to poor picture and video quality. 
BARCLAYS EARLY BUY CALL: In a research note to investors on December 5, Barclays' Sandler upgraded Snap to Overweight from Equal Weight and raised his price target on the shares to $18 from $11.
Since the day Snap's now infamous redesign got its wide release, users have begged Snap to reverse it.
REDESIGN: Along with its last earnings report on November 8, Snap CEO Evan Spiegel said in a letter to investors that the company is redesigning Snapchat to make it easier to use, pointing out that the effort to make the app easier to understand and use comes with "a strong likelihood" of being "disruptive to our business in the short term." Afterward, Morgan Stanley analyst Brian Nowak downgraded Snap to Underweight from Equal Weight, noting that Instagram (FB) competition is only increasing while the company's pending app redesign creates further engagement and execution risks.
For those who forgot to tap on the icon before sending it, they can go My Story, tap on the menu icon on the right, choose the snap to open it and then tap on the download icon in the bottom-right of the screen.
Once you add the Snap to your story, you can still save it during the 24 hour period while it's posted.