Inline Images

Per the org-mode [spec](http://orgmode.org/manual/Images-and-tables.html#Images-and-tables), you can include inline images as links without
any descriptive link text, like this:

[http://farm5.static.flickr.com/4049/4358074549_5efb8b4903.jpg](http://farm5.static.flickr.com/4049/4358074549_5efb8b4903.jpg)

I currently do not support the caption/link syntax, but I can include
the inline image. I recognize the following image file types:

 * .jpg
 * .png
 * .gif
 * .jpeg
