I'm a casual photographer from way back. Do you know what kind of camera I used when I was a teenager? Yes, that's right—a Kodak Disc, an example of which is shown in Figure 1.
The raw truth of the matter is that I didn't take any "selfies" with my old Disc camera; among other reasons, the camera's focal length was too long. I also was selective about who saw my photos because you could hold them in your hand, and they could be shared only with people whom I was physically near or to whom I mailed the prints in an envelope.
Finally, the thought of taking risky or provocative pictures was out because I was sure that the images would get flagged by the photo processor at my local pharmacy. Boy, things have changed with taking simple snapshots in the intervening 30 or so years, haven't they?
Metadata and Exif
In computing nomenclature, the term metadata denotes data that describes other data. Before you accuse me of being too abstract, allow me to explain. The digital photos that you take with your smartphone or point-and-shoot camera contain numerous metadata fields that describe various aspects of the photo's environment, including, but not limited to, the following attributes:
- Camera make, model, and (sometimes) serial number
- Date and time that the picture was taken
- Shutter speed
- ISO setting
- Focal length
- Creator information
- Photographer-defined fields
As you've probably (correctly) guessed, these metadata fields are called Exchangable Image File Format (Exif, often incorrectly spelled EXIF) data. And for some people, notably photographers, Exif data can prove to be a valuable tool.
Take, for instance, the Flickr.com photo-sharing site. As you can see in Figure 2, Exif data is displayed along with each published digital image.
Figure 2 Some photo-sharing websites, such as Flickr.com, display Exif metadata as a routine matter of course
For the record, many photo-sharing websites display image metadata by default, so choose your image host wisely. On the other hand, some social media sites such as Facebook routinely strip metadata from images for privacy concerns. (I'll discuss why metadata removal can be an important topic for you momentarily.)
As it happens, Exif is only (perhaps) the most popular image metadata standards, but there are others. The International Press Telecommunications Council (IPTC) format has been around since the 1970s. The Extensible Metadata Platform (XMP) is a newer image metadata standard developed by Adobe. Although I refer only to Exif metadata in this article, I will teach you how to manage any and all metadata that may be embedded in your digital images.
If you really love the effects that a particular photographer could achieve with his or her photo, studying all the Exif metadata related to that shop can help to make you a better photographer. Another reason to like Exif data is that many current photo-management programs, such as Apple iPhoto, use Exif metadata to categorize your images for you automatically. This can be a great convenience when you need to find that perfect shot from last summer's trip to Disneyworld.
Finally, professional photographers often rely upon image metadata to carry information that is crucial for their business. I'm talking about stuff like copyright notifications and photographer contact information.
Then What's the Problem?
If Exif metadata is so useful for photographers and end users, what the heck is the problem?
In a nutshell, the Exif-related issue that raises some people's privacy concerns is the capability for Exif metadata to store geolocation information. In other words, depending upon the capabilities of your digital camera or smartphone, your photos can have the exact geospatial coordinates of where the photo was exposed encoded in the image.
Do you see the potential problem? This means that if I share a cute digital picture of my cat with my friend. and my friend posts the picture to her Facebook wall, lots of people could (in theory) view the exact location of my home, which is probably where I took the cute picture in the first place.
To get a concrete picture (pun intended) of what I mean, examine Figure 3, which shows you a digital image, its Exif data, and a map that reveals precisely where the photograph was taken.
Figure 3 Apple iPhoto reveals a tremendous amount of information about your digital images
The capability for a smartphone or digital camera to geotag digital images depends upon that device's capabilities with regard to accessing a global positioning system (GPS) networks. And understand that Exif geolocation data can provide great convenience and a "wow factor" as well. I mentioned Apple iPhoto already—this tool can sort your images based upon where they were taken, as well as perform facial recognition.
Any smartphone worth its salt nowadays has both a digital camera and an onboard GPS. Moreover, many of my professional photographer friends purchase GPS add-ons to their 35mm SLR cameras so they can remember where they took their beautiful pictures.
Because Exif is an extensible standard, it is possible for digital photos to store other information that you may not be comfortable leaking to strangers, such as your name, username, e-mail address, and so forth.
Therefore, the salient questions for us to answer at this point are as follows:
- How can we view the Exif metadata that is stored in our digital images?
- How can we remove some or all of the Exif fields?
Well, I am happy you asked—let me answer both of these questions comprehensively for you right now.
Viewing Exif Metadata
In my humble opinion, you don't want to view Exif image metadata by uploading them to photo-sharing website hosts such as Flickr, In a way, it's too late then because the digital images have already been published. Instead, we need to view the image metadata from the privacy of our computer or mobile device.
Yes, it's true that there are web-based Exif viewers (examples include Jeffrey's Exif Viewer and Verexif). However, sharing your images with "utility" sites such as these defeats the purpose of what you're trying to accomplish; namely, enhancing your online security and privacy.
Instead, you need to obtain a free or paid Exif viewer utility. Your options here depend on your operation system or device platform, so let me break down some of your options along those lines.
In Windows 7 or Windows 8, you can see some Exif metadata fields for fun and for free by right-clicking an image file, selecting Properties from the shortcut menu, navigating to the Details tab, and scanning the results as shown in Figure 4. Notice in the figure that we're leaking username and computer name information in the metadata, which could be taken advantage of by a hacker.
Figure 4 Windows 7 has a native Exif viewer, but it is cumbersome to use for several images
Performing the right-click acrobatics is barely acceptable for a single digital image; imagine doing so to scan hundreds of images. The bottom line, and this applies to any operating system platform, is that you need to invest in a quality Exif viewer/editor.
Here are some options for Windows:
As you saw in Windows File Explorer, Apple OS also has a native Exif metadata viewer. Simply right-click your target image file and select Get Info from the shortcut menu. In the Get Info dialog box, expand the More Information disclosure triangle. Voila—you can access a list of basic Exif fields. Figure 5 shows you what this looks like.
Figure 5 OS X provides basic built-in Exif viewing capabilities
If you are looking for a more robust solution, open the App Store and check out one of the following tools:
It makes sense, at least to me, that because the vast majority of your digital images come from your smartphone, you may have need to view and possibly edit Exif metadata fields before you hit that Share button.
Sadly, iOS does not include a built-in Exif viewer, so we'll have to rely on third-party apps. Fire up a connection to the App Store and check out one of the following tools:
To give you a visual frame of reference, take a look at XYZ, which I show you in Figure 6.
Figure 6 On the iPhone or iPad, we can use the Exif Viewer app to parse image metadata
Due to its roots in the open-source development world, Android is a much more extensible mobile operating system than is iOS. Accordingly, we can view the Exif metadata by using a variety of tools.
If a more powerful utility is on the menu, you are, of course, free to browse the Android Store. Here are some app options that are worthy of your consideration:
Yes, I understand that I'm leaving out some platforms such as Linux and Windows Phone. This article isn't a book, for heaven's sake! If you really need specialized information, hit up Google or Bing and run a search like view exif data windows phone and see what results turn up.
Editing and Removing Exif Metadata
Now we arrive at the centerpiece of this article; namely, how we can improve our online privacy by scraping potentially sensitive information from our digital images' Exif metadata. The tool we need to accomplish this task is more powerful than an Exif viewer. Instead, we need an Exif editor that provides us with read and write access to those fields.
As an example, let's assume that you work in a Windows 7 environment, and you want to strip as much Exif data as possible from a folder containing 50 digital snapshots. How do you perform this action?
First, you need to get our hands on an application that can do the job. If you have the money, a premium tool such as Adobe Lightroom is all you need. From the "financially more reasonable" (aka "free") category, I suggest you check out Phil Harvey's ExifTool. This program runs on both Windows and OS X, but in itself uses the command line.
On Windows, just download the ExifTool and the ExifToolGUI ZIP files and then unpack them into the same folder on your computer. Next, rename the ExifTool executable file to ExifTool.exe. Finally, double-click ExifToolGUI.exe to start the tool.
Once you are in ExifToolGUI, find the target image and select it to expose its metadata. Note that ExifTool reveals any and all embedded metadata, not only Exif format. Click Modify > Remove Metadata to invoke the Remove Metadata dialog box, as shown in Figure 7.
Figure 7 The free ExifTool/ExifToolGUI combination gives you complete control over image metadata
Select the metadata you want to remove and click Execute. You're finished—for that photo, anyway.
Ha! I got your attention, didn't I? Don't worry; I'm not being naughty here. Instead I refer the conundrum of your needing to remove Exif metadata from hundreds to thousands of digital images. Do you plan to strip the Exif data on the files one at a time? Of course not; that's silly. Instead, you want to obtain an Exif editor that has batch-editing capabilities.
The bad news here is that you may have to dust off your command-line skills because some of these so-called "advanced" tools have no graphical user interface (GUI).
The good news is that by using batch editing, you can improve your online privacy in a mere fraction of the time that it would take you to manually clean each image file.
Yes, that's the same ExifTool.exe that we downloaded in the previous section. Check this out: To batch-remove all metadata from all JPEG images in a folder, open a command prompt/terminal session on your computer, navigate to the target folder, and run the following command:
exiftool –all= *.jpg
Pretty cool, eh? Due to space constraints, I'm obviously leaving out some steps, such as how to navigate your computer via the command line.
The Take-Home Message(s)
In conclusion, I want to leave you with a summary of what I think are the most important action items from this article.
Know Your Device's Capabilities
You may be able to restrict the Exif data that your digital camera employs in the first place. Read your owner's manual or ask around on the manufacturer's support forums to learn what's possible here.
Don't Let Convenience Turn into Complacence
You may truly enjoy how Exif fields like geolocation make it more intuitive to manage your digital image store. Hey, that's cool! Just be careful to scrape some or all of the Exif data before you share a copy of your source image. We can trust that only authorized parties will see our iPhoto library on our Mac, but we cannot say the same for an image that we send to our colleague via an e-mail attachment.
Exercise Digital Hygiene when You Use Social Media
Besides the traditional bromides such as "Be careful what you share in social media" and "You can't take it back once you send it," I would also put in a plug for getting into the habit of sanitizing your digital media prior to your submitting it for online publication in any form. My goal for you is that it will be almost unthinkable for you to share any digital image online without ensuring that you are not also unwittingly revealing personally identifiable data (PID).