New Post Image Support

[oubiwann]

Dragon 1.0 has a new default image implementation. Currently, all posts will get one of 8 possible default images (tied to a numeric hash of the post title). Default images are of the following type:

• post image (900x300)
• headliner image (750x300)
• small circle crop (200x200)
• thumb circle crop (100x100)
• small thumb (50x50 -- not a separate image; CSS-based using thumb)

However, we don't want all posts to use a default image. We'd like the option to override this; many of the old posts do have their own primary post image. Here's what we need:

• New RFC5322 headers for images:
  • Header-Image: (used by the post)
  • Headliner-Image: (used on the main pain when it's the first headline)
  • Small-Image:
  • Thumbnail-Image:
• New schema entry for post images
• New data structure for all of a post's images
• New queries for setting and getting post images
• New .rfc5322 source file processing step for image headers
• Update existing default images to be stored in DB during processing of files
• Logic for default images to be used in the case where no Main-Image is provided
• If only a Main-Image: is set, to generate the other images
  • call to cmd line tool in another thread
  • define default resizing and cropping of main image to generate derived images
• Update current template usage of default images to instead pull from DB (via functions in the data.clj file)