I wrote this module because I needed a way to strip off location (GPS) metadata from uploaded photos for a private Gallery3 site I run for family members. So, by default, the module is configured to strip the GPS/location EXIF and IPTC tags that I've personally encountered. However, it can also be configured to strip any tags you like.
The tags you configure for removal will be removed from all instances of the image: the original, the resized version, the thumbnail, and the album covers.
It cannot (yet) remove tags from existing images. There should be an option to do so in the module's configuration page, I know, but I just haven't got any more time right now to work on this. If someone would like to add this functionality, feel free to do so and please send me a patch so I can update it in git.
-j