Why is the iPhone 7 sending all pictures inline in emails?

Two days ago, I switched from the iPhone 5 to the iPhone 7 and now any pictures I send (whether jpeg or png screencaps) to Outlook are being sent inline as opposed to as attachments that can all be downloaded at once. How do I go back to sending as attachments that can all be downloaded at once? It's a pain for people to be downloading each inline picture individually!