Easiest is to screen shot the photo or
Gallery
Select photo
Click pencil
Click the bent arrow around the square ish icon
Pull the corners that are highlighted to crop the photo
Save photo
Click add attachments
Choose file
Click files not camera
Click on photo
It should be the top photo on the list
Click select if prompted
Click post
You have to type some words also in the post. I don't believe you can post just pictures
