|
16
|
1 <!DOCTYPE html>
|
|
|
2 <html>
|
|
|
3 <head>
|
|
|
4 <meta http-equiv="content-type" content="text/html; charset=UTF-8">
|
|
|
5 <title>Introducing ExifWasher</title>
|
|
|
6 <style>
|
|
|
7 html { font-family: "TeX Gyre Schola", serif; }
|
|
|
8 h1, h2, h3, h4, h5, h6 { font-family: "Avenir Next", sans-serif; }
|
|
|
9 pre, code, kbd, samp { font-family: "Menlo", monospace; font-size: 85%; }
|
|
|
10 </style>
|
|
|
11 </head>
|
|
|
12 <body>
|
|
29
|
13 <h1>Introducing JpegWasher</h1>
|
|
16
|
14 <h2>Executive Summary</h2>
|
|
|
15 <p>This program makes it easy to remove metadata from the digital images you
|
|
|
16 create.</p>
|
|
|
17 <h2>What is “Metadata” and Why Would I Want to Remove It?</h2>
|
|
|
18 <p>You may not realize it, but image files can (and typically do!) contain
|
|
|
19 more than just image data. These data can include your camera make, model,
|
|
|
20 and serial number; the location where you took the photo; the software you
|
|
|
21 used to edit the photo (and what editing steps you did); etc.</p>
|
|
|
22 <p>One of the most powerful uses of photography is to graphically document
|
|
|
23 things that the wealthy and powerful might wish to remain concealed. The
|
|
|
24 evils of slavery, child labor, poverty, war, and imperialism have all been
|
|
|
25 documented photographically, and such photographs have often proved
|
|
|
26 instrumental in helping to motivate social change.</p>
|
|
|
27 <p>Because of the metadata they contain, digital photographs contain data
|
|
|
28 which has been used to determine who took them, and in some cases to exact
|
|
29
|
29 retribution against those photographers. JpegWasher makes it easy to see
|
|
16
|
30 and remove the privacy-compromising metadata in your images.</p>
|
|
|
31 <p>Even if your images are not of such a sensitive nature, that extra data
|
|
|
32 takes up space. It is not uncommon for a 100 KiB image to contain 20 KiB
|
|
|
33 of metadata in it; if that image is on a web page, that makes for 20 KiB
|
|
|
34 of wasted network usage each time the image is sent.</p>
|
|
29
|
35 <h2>What Makes JpegWasher Different from Other Metadata Editors?</h2>
|
|
16
|
36 <p>Simply put, it is designed to <em>safely</em> remove <em>unimportant</em>
|
|
29
|
37 metadata from JPEG files.</p>
|
|
16
|
38 <p>There are plenty of general-purpose image metadata editors out there, and
|
|
|
39 these tools can be employed to remove unimportant metadata. The trouble
|
|
|
40 is, they are not user-friendly: it is up to you, the user, to know which
|
|
|
41 metadata are unimportant, and to delete it.</p>
|
|
|
42 <p>There can be literally <em>hundreds</em> of bits of metadata in an
|
|
|
43 image, and <em>not all are safe to remove</em>. In particular, if you
|
|
|
44 accidentally remove color-management metadata, computers that don’t handle
|
|
|
45 images without color-management metadata properly (I’m talking about <em>you</em>,
|
|
|
46 Apple Computer, Inc.) will display colors that often look all “washed-out”
|
|
|
47 or otherwise incorrect.</p>
|
|
|
48 <p>Likewise, there are already plenty of simple-to-use, user-friendly tools
|
|
|
49 out there for cleaning the metadata out of image files, but they
|
|
|
50 inevitably delete <em>all</em> metadata, resulting in files that often
|
|
|
51 display improperly. Also of concern, many of these “tools” are actually
|
|
|
52 online services. If you’re concerned about your privacy, why would you
|
|
|
53 trust the images you’re processing to some unknown third party, who may be
|
|
29
|
54 linked somehow to those who might want to retaliate against you?</p>
|
|
16
|
55 <p>I wrote this program because I wanted there to be a quick, easy way to
|
|
|
56 scrub images before they even left a photographer’s computer and made
|
|
|
57 their way onto the Internet, and for that program to leave vital metadata
|
|
|
58 alone, so that the resulting images continue to display properly.</p>
|
|
29
|
59 <h2>JpegWasher Washes More than Just Exif Metadata</h2>
|
|
|
60 <p>Jpeg is the most common type of metadata, but image files commonly
|
|
16
|
61 contain compromising XMP or IPTC data, particularly if they have been
|
|
29
|
62 edited with a tool like Photoshop. JpegWasher will seamlessly deal with
|
|
16
|
63 these kinds of metadata, too. It tries to do as thorough a job as possible
|
|
|
64 of scrubbing possibly compromising metadata from your images.</p>
|
|
29
|
65 <h2>Using JpegWasher</h2>
|
|
|
66 <p>Just double-click on the JpegWasher icon and a main window should open
|
|
16
|
67 up. Either choose the File… Wash from the menu bar, or just drag image
|
|
29
|
68 files onto the main JpegWasher image.</p>
|
|
|
69 <p>When JpegWasher opens an image, it displays all the metadata it finds.
|
|
16
|
70 That metadata will be run through an internal whitelist, and any data
|
|
|
71 whose “key” is not found on the whitelist will be automatically selected
|
|
|
72 for deletion.</p>
|
|
29
|
73 <p>If you disagree with JpegWasher’s decisions, you can check or uncheck the
|
|
16
|
74 boxes next to the metadata in question. When you are satisfied with the
|
|
|
75 choice of metadata to be scrubbed, click “Wash” and all offending metadata
|
|
|
76 will be removed. A dialog will pop up showing the metadata remaining in
|
|
|
77 the new, washed file.</p>
|
|
29
|
78 <h3>Important: Run JpegWasher Last!</h3>
|
|
17
|
79 <p>Most image-editing tools insert telltale bits of metadata into the output
|
|
|
80 they create. Thus, only way you can create a file with the minimum amount
|
|
29
|
81 of metadata in it is to run JpegWasher as the final step in your image
|
|
17
|
82 preparation.</p>
|
|
29
|
83 <h3>Washing Non-JPEG Images</h3>
|
|
|
84 <p>In short: it’s possible, but it is not recommended unless you <em>really</em>
|
|
|
85 know what you’re doing.</p>
|
|
|
86 <p>JpegWasher is called JpegWasher for a reason: it is geared to cleaning
|
|
|
87 metadata in <em>JPEG</em> files. Different types of images use metadata
|
|
|
88 differently; metadata that would be extraneous deadwood in a JPEG can be
|
|
|
89 critical to interpreting other image file formats correctly. JpegWasher’s
|
|
|
90 built-in whitelist is geared to what must be retained when washing JPEG
|
|
|
91 images, so <em>careless use of JpegWasher is likely to damage non-JPEG
|
|
|
92 files.</em> It is for this reason that JpegWasher will warn you if you
|
|
|
93 attempt to open and wash a non-JPEG file with it.</p>
|
|
16
|
94 <h2>Output Files</h2>
|
|
29
|
95 <p>JpegWasher never modifies an existing image file. Instead, it creates a
|
|
16
|
96 new file of the same type but with “_washed” appended to its name. For
|
|
|
97 example, processing <code>foo.jpg</code> will create <code>foo_washed.jpg</code>.
|
|
|
98 By default, the new file will be created in the same directory as the file
|
|
|
99 being washed.</p>
|
|
29
|
100 <h2>JpegWasher is Configurable</h2>
|
|
16
|
101 <p>Both the whitelist and the destination directory for the washed files are
|
|
|
102 user-configurable in the Preferences menu.</p>
|
|
|
103 <h3>Configuring the Whitelist</h3>
|
|
|
104 <p>There are two kinds of whitelist entries: those that match an entire
|
|
|
105 metadata key, and those that match a key prefix. The latter end in an
|
|
|
106 asterisk. The whitelist is case-sensitive; i.e. the entry <code>exif.image.colormap</code>
|
|
|
107 <em>will not</em> match the <code>Exif.Image.ColorMap</code> key.</p>
|
|
17
|
108 <h2>That’s about It</h2>
|
|
29
|
109 <p>JpegWasher does not, and probably never will, do anything but remove
|
|
|
110 extraneous metadata from JPEG files.</p>
|
|
17
|
111 <p>First, I have no desire to re-invent the wheel. There are already
|
|
|
112 excellent open-source tools like Gimp for image editing, and ExifTool and
|
|
29
|
113 Exiv2 for general-purpose metadata editing (in fact, JpegWasher is built
|
|
17
|
114 on top of Exiv2). If you need the functionality of some other tool,
|
|
|
115 download and use it!</p>
|
|
29
|
116 <p>Second (and more importantly), I want JpegWasher to be simple, and
|
|
17
|
117 therefore easy to learn and easy to use. The more challenging an
|
|
|
118 information-security tool is to use, the less likely it is to be used
|
|
|
119 frequently, and the more likely it is that compromising information gets
|
|
|
120 disclosed.</p>
|
|
16
|
121 </body>
|
|
|
122 </html>
|
