Photos can be shared as long as sharing is enabled for that specific photo. To share a photo, select a photo and tap on the share icon located at the upper right corner of the screen. You will be presented a share sheet with the available social platforms to share the photo to. Select a social platform and follow the on screen directions to post.
To enable screen reader support, press shortcut ⌘+Option+Z. To learn about keyboard shortcuts, press shortcut ⌘slash.