What is EXIF Data and why is it important to know

When you capture a photograph with your Phone, professional camera or any of the new imaging device, the camera not only save the present date and time into the image file, but many other information as well, even the camera settings. The data that’s recorded by the camera into the picture file might include details on the camera model, the lens that was used, shutter speed, aperture, length of focal and etc. Most of the modern cameras and phones are GPS enabled and therefore they will store the location coordinates (latitude and longitude) within the pictures.
All this “metadata” is embedded into every picture with Exif format that may simply be viewed or red by most image editing programs as well as by on-line picture sharing websites like Flickr and Picasa.  “Exchangeable image file format (officially Exif) is a standard that specifies the formats for images, sound, and ancillary tags used by digital cameras (including smartphones), scanners and other systems handling image and sound files recorded by digital cameras. “

If you like the picture or would like to know more about the camera brand, the lens settings that were used, here’s what you can do do.

Go to  http://metapicz.com/#landing or http://exif.regex.info/exif.cgi   and upload the picture (or if you found it on web, just copy-paste the image URL). The tool will give you the report of all the meta data stored in the picture along with the location information. As an alternative, you can use Google Picasa, Windows Photo Gallery, as well as many  other software that can display Exif data from pictures.
Reasons to modify the data? For instance, if the time stamp on images are  wrong and you want to correct it or you want to add your name to metadata or simply due to security reasons you just want to remove all the information stored in the picture.  One of the best editors in this case is Windows Explorer. How? right click any image, click on Properties and click the Details tab. Now You can edit a the metadata associated with that image. Windows explorer will not let you edit GPS information, but Picasa is a good software for doing it.
To remove all the metadata from a picture, just right-click the files inside Windows Explorer and choose Properties. Now click the Details tab and select the option that says “Remove Properties and Personal Information.”
Choose “Remove the follow properties from this file” followed by “Select All” and click OK. All the private metadata tags are now erased from the photograph. Easy!

With new generation phones and devices, it is more and more difficult to maintain privacy and secrecy of your life, specially when behavioral based Advertising is on its peak . More and more companies are trying to gather personal information. One of the platforms I want to mention is Facebook’s photo recognition.  When the picture is added to Facebook, its server is analyzing the image, looking for objects, scene and people. Even if you don’t put any description or information Facebook can check and analyze the image and determine what is it all about. Facebook uses the algorithm or the machine generated captions to have your image more accessible to blind users as well as to study and target advertising.

If you are interested in viewing how Facebook recognizes your image, you can check the tag associated with the image. Here is how to:

1. Open any picture in thumbnail on the Facebook (to view larger version of the picture)

2. Right-click the picture and click Inspect element to open the Chrome Dev Tools. This should work with most of modern browsers.

3. Look at the alt attribute of the image tag: <img Class= “spotlight” alt=”Image may contain: Description”.  If there is no tag or description you may need to expand the <div> tag or simply Facebook has not analyzes the image yet.

Here are some examples:




The software of Facebook’s picture recognition covers multiple concepts including food, objects , people’s expression (are they smiling, crying, laughing?), sports, nature (sky, mountains, indoor), and much more. My favorite one is if it is a group photograph, Facebook can actually count and tell you the exact number of people in picture (it includes pictures on the wall(s) as well).

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