Everything is changing on Django those days, and many people contacted me because StdImage stopped working with trunk.
Basically all major changes (except GeoDjango) affected it, such as change from newforms to forms, signal refactoring, and file storage refactoring. Now it's up to date.
Remind that django-stdimage is a Django application that provides a standardized image field(standard name including row id, standard size, and ability to create automatic thumbnails, also standarized of course).