Oh, silly me. It took me some time to go through dal.py and realize I made a mistake by running above commands in web2py shell.
There db.adapter will be SQLite and I've problem with gae. Now, here is the actual result. print db.pictures.fields() * ['id', 'image', 'words', 'rating', 'entry_by', 'image_blob']* print db.pictures.image.uploadfield *image_blob* print db._adapter.uploads_in_blob *True*
