From any chat you can send a picture to any members, for this you must press the button that you will see on the left at the bottom of the screen.
By pressing this button, you must choose whether the picture will be send from the camera or selected from the gallery of the device.
The other users will see the pictures on their chat screen.
If you click on picture, you can zoom it.
You also have the option to see all the images of a certain chat, for this from the chat screen you must click on the title to open the details screen, where you will see the Multimedia option.
If you click on the Multimedia option, you can see all the images of that chat channel as a mosaic.
Note: In case you are a teacher user, you can also send images from the screen of a story.