The best is Hold to Preview, which is exactly what it says.
The moment you take your thumb off the button, it'll send—unless you drag your finger tip up to the universal "no" symbol, the circle with the diagonal line through it.
Features and Functionality DO Camera has some extras features, such as an icon to swap between the front-facing and rear-facing cameras.
You can toggle between the text and markup options, but know that the text always appears in the foreground.
Using DO Camera can replace having to open other apps where you might use the image, such as Facebook, Evernote, Twitter, Google Drive, Gmail, Flickr, One Drive, Dropbox, Word Press, Tumblr, and Slack. anything with your photos, you have to log into you IFTTT account (or create a new one).
In addition, you must connect whatever channels you want to use.
It all runs through your normal IFTTT account, even though you have a new app for the action. With more traditional IFTTT recipes, the trigger is something that happens in the online world, and not necessarily an action you purposefully take. Another example is "If I leave my home (as detected by the geolocation data on my phone), then automatically turn off my Philips Hue smart light bulbs." In neither case did the user have to do anything with their phone to start the chain of events. With the DO Camera app, as well its sister apps DO Button and DO Note, however, the action occurs when the user opens the app and presses a button, or uses a quick action shortcut from the Notifications window.
IFTTT's main competitor is Zapier, an equally useful service that does not offer a button to trigger actions, like the ones you'll find in DO Button, DO Camera, and DO Note.
You choose the recipes when you first set up the app.