Open Instagram and go to Direct Messages
Select the chat you want to send the photo to
Tap the camera icon or the photo gallery icon
Take a new photo or choose one from your gallery
Before sending, tap the view option if available
Select View Once or Allow Replay
Send the photo
For disappearing in chat, use Vanish Mode if available
Open the chat, then swipe up from the bottom to turn on Vanish Mode
Send the photo while Vanish Mode is active
Turn off Vanish Mode by swiping up again when finished