When you want to add a photo(s) to your post, photos, not videos, this is how it is done.

With the cursor in the line you want the photo, select "Attachments" at the bottom of the text box. Select to add photos from your library. Search your photos nd select the photos you want to post.

After you have selected your photos, select to start upload.

After the upload is finished, your photos will appear in the text box. For me, the text never cooperates, but the photos are there.