1. have your pictures in a place on your computer where you can retrieve them
2, REPLY, write message and then Scroll down to "MANAGE ATTACHMENTS"
3. Browse and click on picture you want to post..click on OPEN
4. UPLOAD picture and CLOSE
From either computer or mobile device, you don’t need to close anything. You can upload all five allowed photos one after another. Just choose the next file and repeat the upload, close after all your pictures have been attached.
PS: To be clear, don’t use the “quick reply” window below, but “go advanced”.