The photo file contains metadata - EXIF, etc.) that is added by the camera software and can be inserted using software by anyone opening the file.
FileMaker uses GetContainerAttributes() to read this data and make it available for use in a variable or field.
If you take the picture using IOS Camera you get the GPS data. If you use the GO insert step, the GPS data is not inserted into the photo file. You can grab it (if you have the time) using Location and set that into a field in the record.
There is also information in the file that GO does not grab as can be seen in the graphics below. I used Troi's File plugin to get the data on the left for comparison. There may be other data in the file that could be read by another plugin.
The graphics below show the attributes in two files. The columns are Troi Files plugin and then the attributes of the full image and then a thumbnail. Notice how the information differs.
Troi does not supply an MD5 value and the full image and the thumbnail have different MD5 values.
This data is taken from a photo file created using IOS Camera and exported to a file.
This data is from a photo file taken using FileMaker GO and inserted into a container field.
It would be interesting to implant a copyright and other personal information in the images.
Also note that it may be possible (maybe not) to glean this data from the photos posted to the Internet. For instance, your latest vacation photos will tell where you are and this isn't at home....
I use Apple's camera and have my computer set to save a copy of the photos to Dropbox. I then import the files. I do this just for the GPS data and because it is faster using IOS camera compared to GO and capturing the GPS using Location. (I also forget and sometimes use iTunes to download a clone of the file and lose the photos I have taken with GO )