How To Delete Image Metadata
Digital image files contain piles of metadata, which is basically useless overhead and, worse, a privacy problem (especially things like edit history or programs used). Certain things, however, are useful for archiving (date taken, camera model).
To look at these lines of code, one needs a code editor, e. g. Notepad++. But do not think of using it to delete unwanted code! It will ruin the picture. (It can be restored in Photoshop, but that is not the kind of work flow that makes one’s day.)
The most annoying garbage producer was the infamous Windows [Live] Photo Gallery. It was convenient and easy to use, but it messed up every picture in the long run by saving JPG over and over again – without even asking at which quality!
Today we know that one should not save a JPG ever again after it leaves the camera. JPG is lossy, even if the camera uses the best existing compression algorithm.
If a JPG has to be edited, it should first be converted to a Tag Image File (TIF).
The Internet is full of people asking how one can strip image files of useless overhead. Some hate the idea of a few KB extra, others want to edit images and pretend they were never edited.
The answers I found were not entirely satisfactory. EXIF editors do exist, but they don’t do the job right and delete only certain types of tags. And some of them are not capable of batch processing, which is vital for handling hundreds of image files efficiently.
Solution:
Open an older version of Photoshop (e. g. version 11), go to “Process Multiple Files”, select the source and the target folder, and let Photoshop convert the JPG to PNG automatically. Result: The overhead is gone. All the metadata have disappeared, including date taken and camera model. The reason for this is simple; PNG can also create and store metadata, but they are not compatible with the EXIF format. Therefore EXIF data are not saved.
After this operation you convert the PNG to TIF and reinsert the information you need in the Properties dialog in Windows, which allows batch processing too.
Job done! No more “Unique image ID”, no more “Microsoft image”, no more “Windows Photo Gallery”. To call an image a “Microsoft image” just because it was opened and saved once in the Photo Gallery is a cheek anyway.
TIF is by far the best format, and images can be edited hundreds of times without quality loss in any editor as it is nonproprietary.
PNG is also good, nonlossy like TIF, but compressed. Saving files takes longer, and some image organizers cannot read PNG. But Internet browsers have no problem with this format.