XF 2.0 Most optimized way to add an image in a post (in terms of page loading)

[abdfahim]

I am wondering which results in the quickest loading and minimum server load (or query) of the followings (or, are they all same?)

1. Insert an image in the post by uploading an image
2. Insert an image in the post by URL using a media item link on the same site
3. Embed an image from the gallery

provided that I am talking about exactly the same image.