The ExifTags module exposes two dictionaries which provide constants and clear-text names for various well-known EXIF tags.
The TAG dictionary maps 16-bit integer EXIF tag enumerations to descriptive string names. For instance:
>>> from PIL.ExifTags import TAGS
>>> TAGS[0x010e]
'ImageDescription'
The GPSTAGS dictionary maps 8-bit integer EXIF gps enumerations to descriptive string names. For instance:
>>> from PIL.ExifTags import GPSTAGS
>>> GPSTAGS[20]
'GPSDestLatitude'