Try this: update to WordPress 4.2 beta 2 and drag the “Press This” to your bookmark bar. Visit a URL that you like and poof.
I just did that on a Flickr photo and I was able to select the image from the options and below is the result.
Source: Custom Built HG 1/144 Acguy ( R2D2 Color Ver) | Flickr – Photo Sharing!
The post is complete with a source link for attribution. I added some categories and saved as a draft. The whole update to Press This really is well done. It’s more attractive and easier than ever.