Image size extractor (run after EXIF to ensure it is correct)
thumbnail generator (should be same format as original file)
- extract JPEG thumbnail
- extract embedded PNG thumbnail
- scan .thumbnails/
- generate manually

JPEG and PNG XMP extractor (test with F-Spot)

Do something about sub-galleries, i.e. 2004-Christmas should be Xmas-Harlow, Xmas-Stansted, NewYear

Clone Image::MetaData::JPEG in Python

Remove use of W3CDate I guess

Standard makefiles for users to include

Integrate directory extractors into summary generator for titling galleries.

Handle sub galleries as categories. Running summary on a subfolder and then
treating it as a gallery will create a category.