Photos taken on smart phones and newer cameras can have a lot of metadata in them. This metadata can include your GPS location, software you have used to edit the photo and the device they were taken on. While this metadata can be handy in remembering where you took the photo or what the photo is of, sharing this data can pose a security risk.

In preparing photos for this site, I wanted to remove all but the important metadata from each image.

A great command line tool to do this with is `exiftool. It is capable of viewing and editing image metadata on many different file types and metadata formats.

To view the metadata of a file, you simply call exiftool giving it the name of the photo.

$ exiftool photo.jpg
ExifTool Version Number         : 11.88
File Name                       : test.jpg
Directory                       : .
File Size                       : 118 kB
File Modification Date/Time     : 2020:08:09 18:10:45+01:00
File Access Date/Time           : 2020:08:09 18:10:46+01:00
File Inode Change Date/Time     : 2020:08:09 18:10:45+01:00
File Permissions                : rw-rw-r--
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
JFIF Version                    : 1.01
Exif Byte Order                 : Little-endian (Intel, II)
ISO                             : 50
Exif Version                    : 0220
Date/Time Original              : 2019:01:14 13:33:19
...

The basic command to remove all metadata from an image is using -all=

$ exiftool -all= photo.jpg
    1 image files updated

$ exiftool -all= folder/*.JPG
    73 image files updated

To remove all but a set list of metadata, you can use -all= along with a set argument for each tag you want to keep. The set argument is in the format -TAG<TAG, which tell exifdata to set the value of TAG from the current value of TAG.

Here is the command I used to remove all metadata except the date, tags, title and description.

$ exiftool -all= "-DateTimeOriginal<DateTimeOriginal" "-TagsList<TagsList" "-Title<Title" *.jpg

Determining the name of your tag you want to keep is as simple as finding the metadata in the output of exiftool and then removing the spaces and slashes from the name. For example Date/Time Original (as shown above) would become DateTimeOriginal.

I have noticed that running the command above will add a value for XMP Toolkit to the image. If you want to get rid of this, you can add -XMPToolkit= to the command

$ exiftool -all= "-DateTimeOriginal<DateTimeOriginal" "-TagsList<TagsList" "-Title<Title" -XMPToolkit= *.jpg