Desktop version:
To send a photo, navigate to the “Messages” tab in "Your activity" section. Choose the user you wish to send a photo to from the list of users located on the left side of the screen.
Click the “Media” button and select the photo you want to send.
Mobile version:
To send a photo, navigate to the “Messages” tab (you can find it on the bottom of the page). Choose the user you wish to send a photo to from the list of users.
Click on the paperclip icon and select the photo you want to send.
Please take note that the size of each file should not exceed 7 MB, and images must not be smaller than 333 by 333 pixels.
If you are unable to upload a photo in a chat, please follow the instructions in this article.