Confused on how to add a photo to my post that is in the gallery, whats the easy way?

Pretty simple to add a photo that is already upload to a gallery here into a post.

When entering a new post, just use the "Content Selector" (It looks like a calendar) button on the top tool bar and then just select the photo. After selecting the photo, you can also select the image size that you insert into the post.

Hope this helps.

Now that was easy.