iPhone 7 unable to Send photos using iMesaage

Apple has provided iMessage in all their iPhones to send pictures, When you send a photo/picture or any media file (now we're talking videos too) through the messages app, it can be sent via iMessage or as an MMS.

But many users after the upgrade to iOS 11 find issue with photo share using iMessage.When want to share a picture, noticed that the green message icon is missing from the send to/sharing list from the photos app. The icon was there with iOS10 but after the iOS11 update, when  in photos and want to send a selection via iMessage, you may not see  that option...only email, airdrop...not iMessage.

Fix: How to fix not able to send photo using iOS 11

When Contacted to Apple support and indeed they confirm that specific functionality was removed as part of iOS11 update.  But in case you want to transfer the photo using iMessage in iOS 11

Make sure MMS is Turned On: Go to Settings → Messages → and make sure MMS Messaging is turned on.

Now when you hit the box with arrow to share on picture, swipe to the left, until you see the ellipsis with the More beneath it. Tap on that, and you should find the Message option.
I hope this should help you to share photo using iMessage in iOS 11.