You can do that now, but I don't recommend it. Once you post the picture, click on it and set it to align left by clicking on the left-align icon, just to the right of the big "A" for font color.
Then drag it to various spots in your text until the post looks the way you want it. This is what it will end up looking like.
Since you cannot control the pacing between the photo and the text, this doesn't look very good. The text is right up against the picture.
It might be best to not try to wrap a photo around an image. This looks really bad.