File Information (EXIF) – What your photos can say…

Do you post pictures online? E-mail them to friends? When you do you might be sending more information than you think.
Take a look at the information below, this is all from a single picture I took with my phone. This information is embedded in the image as metadata and is used by various applications and tools.
Take a look over the information and I’ll explain more below.

File Size                       : 2.1 MB
File Type                       : JPEG
MIME Type                       : image/jpeg
Exif Byte Order                 : Big-endian (Motorola, MM)
Make                            : Apple
Camera Model Name               : iPhone 5
Orientation                     : Rotate 90 CW
X Resolution                    : 72
Y Resolution                    : 72
Resolution Unit                 : inches
Software                        : 7.1.1
Modify Date                     : 2014:05:03 11:32:20
Y Cb Cr Positioning             : Centered
Exposure Time                   : 1/847
F Number                        : 2.4
Exposure Program                : Program AE
ISO                             : 50
Exif Version                    : 0221
Date/Time Original              : 2014:05:03 11:32:20
Create Date                     : 2014:05:03 11:32:20
Components Configuration        : Y, Cb, Cr, -
Shutter Speed Value             : 1/847
Aperture Value                  : 2.4
Brightness Value                : 9.095280499
Metering Mode                   : Multi-segment
Flash                           : Off, Did not fire
Focal Length                    : 4.1 mm
Subject Area                    : 1357 1275 456 457
Run Time Scale                  : 1000000000
Run Time Epoch                  : 0
Run Time Value                  : 65539364512708
Run Time Flags                  : Valid
Sub Sec Time Original           : 334
Sub Sec Time Digitized          : 334
Flashpix Version                : 0100
Color Space                     : sRGB
Exif Image Width                : 3264
Exif Image Height               : 2448
Sensing Method                  : One-chip color area
Scene Type                      : Directly photographed
Exposure Mode                   : Auto
White Balance                   : Auto
Focal Length In 35mm Format     : 33 mm
Scene Capture Type              : Standard
Lens Info                       : 4.12mm f/2.4
Lens Make                       : Apple
Lens Model                      : iPhone 5 back camera 4.12mm f/2.4
GPS Latitude Ref                : North
GPS Longitude Ref               : West
GPS Altitude Ref                : Above Sea Level
GPS Time Stamp                  : 18:32:11.58
GPS Img Direction Ref           : True North
GPS Img Direction               : 356.9633028
Compression                     : JPEG (old-style)
Thumbnail Offset                : 1254
Thumbnail Length                : 9119
Image Width                     : 3264
Image Height                    : 2448
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:0 (2 2)
Aperture                        : 2.4
GPS Altitude                    : 60.3 m Above Sea Level
GPS Latitude                    : 37 deg 55' 52.24" N
GPS Longitude                   : 122 deg 1' 51.43" W
GPS Position                    : 37 deg 55' 52.24" N, 122 deg 1' 51.43" W
Image Size                      : 3264x2448
Run Time Since Power Up         : 18:12:19
Scale Factor To 35 mm Equivalent: 8.0
Shutter Speed                   : 1/847
Create Date                     : 2014:05:03 11:32:20.334
Date/Time Original              : 2014:05:03 11:32:20.334
Circle Of Confusion             : 0.004 mm
Field Of View                   : 57.2 deg
Focal Length                    : 4.1 mm (35 mm equivalent: 33.0 mm)
Hyperfocal Distance             : 1.89 m
Light Value                     : 13.3

So lets take a look at some of the basics… Things like Camera Make & Model (Apple, iPhone 5), the date and time (2014:05:03 11:32:20.334), various camera settings and image details like focal length, field of view, shutter speed, image size, etc. Then we get to some good stuff, the location the image was taken at. If your device has GPS, it will geo tag the photo. You can see that information listed above in the GPS Position field (37 deg 55′ 52.24″ N, 122 deg 1′ 51.43″ W). It simply takes typing that into Google Maps, and you can see exactly where the picture was taken (with a varying degree of accuracy).
This is all called EXIF (Exchangeable image file format) data. This is a standard format used by images for storing extra data to be associated with the image. It’s been in use in one form or another since the mid 90s and is now implemented in pretty much any device that takes a picture.
So why is any of this important?
The short answer is, it isn’t, but it is also very important at the same time. The reason for this is that in most cases you probably don’t, or shouldn’t care if people have this information. And often it can be helpful. But if you take it all into account, all of the places that you take pictures and post them to Facebook, Twitter, Instagram, etc. They all have this information. And over time, that location information can build detailed information on habits, people you know, the things you do, when you do them, and who you do them with.
The nice thing is most of these services strip off the information, so your friends, or enemies, may not be able to directly download the information, but the companies that you upload the photos to definitely have all of that information, and you can make a safe bet that they are storing it, forever.
It’s scary, if you zoom out and look at the information from a 1000ft view, across multiple users in a system, you can correlate the data to make associations. Say you go to a restaurant and take a photo and post it… Many other people do the same, now you can analyze that data and see who goes to what restaurant for lunch, what time you generally eat, maybe even who you meet for lunch. With enough time and information, and trend analysis, you can figure out a persons life with a terrifying degree of accuracy.
This is all just one aspect of things, just simply by uploading a photo, all of this is available. If you take into account browsing history, tracking cookies, credit card usage, camera footage, … The list goes on and on… your whole life is accessible. And it’s all online, private industry has it, the government has it, and hackers can get their hands on it.
You can extrapolate that type of information out to many, many, many things; the stores you like to go to, and when, to the people you are routinely around, etc. Then if you add things like facial recognition on top of that (Facebook definitely has this implemented) you can really get creative… Think about it.
You can really tumble down the rabbit hole with all of this when you throw in things like purchase history at stores, you can really get a lot of information. e.g., how Target knew a teen girl was pregnant before her father
So, just remember, we already know everything. 😉
Are you making a tinfoil hat yet?


    1. I’m not entirely sure, from what I could find, only certain devices added that value to EXIF information and I haven’t been able to find any reference to what, specifically, it is. I have a feeling it has something to do with the devices run time. But I haven’t been able to find any real specifics on it.

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