Its one thing to have a piece of data but its another thing to be able to get the metadata about said data. ExifTool (http://www.sno.phy.queensu.ca/~phil/exiftool/) is a tool that will allow just that. Its command line based but there is a GUI version as well called pyExifTool (https://hvdwolf.github.io/pyExifToolGUI/). The tool not only allows you to read the metadata but also change it, if necessary. A person could also add his or her own custom tags as well. Below is an example of using the program.
Note: My JPG file name is called pic11.jpg
1) Examine the file using ExifTool
sansforensics@siftworkstation:~/Desktop$ exiftool pic 11.jpg
2) Notice in the output it says the picture was made with Adobe Photoshop CC (Macintosh) as listed next to Software (last line).
ExifTool Version Number : 8.60 File Name : pic11.jpg Directory : . File Size : 85 kB File Modification Date/Time : 2015:04:19 12:25:38-07:00 File Permissions : rw-r--r-- File Type : JPEG MIME Type : image/jpeg Exif Byte Order : Big-endian (Motorola, MM) Photometric Interpretation : RGB Orientation : Horizontal (normal) Samples Per Pixel : 3 X Resolution : 72 Y Resolution : 72 Resolution Unit : inches Software : Adobe Photoshop CC (Macintosh)
3) In this case I want to change this for whatever reason to show it was created using Adobe Photoshop CC (Windows7)
sansforensics@siftworkstation:~/Desktop$ exiftool -exif:software= “Adobe Photoshop CC (Windows7)” pic11.jpg
4) Verify the change by running the tool again against the picture
sansforensics@siftworkstation:~/Desktop$ exiftool pic 11.jpg
ExifTool Version Number : 8.60 File Name : pic11.jpg Directory : . File Size : 85 kB File Modification Date/Time : 2015:04:19 13:00:01-07:00 File Permissions : rw-r--r-- File Type : JPEG MIME Type : image/jpeg Exif Byte Order : Big-endian (Motorola, MM) Photometric Interpretation : RGB Orientation : Horizontal (normal) Samples Per Pixel : 3 X Resolution : 72 Y Resolution : 72 Resolution Unit : inches Software : Adobe Photoshop CC (Windows7)
While this was a quick example of using the program, there are a ton of other variations of using it as well. The man pages will list the compatible file types and meta information. There will also be some file types that can be read but not written to.