If you're not careful, your digital photos could reveal things to other people that you didn't intend for them to see. But is Photoshop to blame? I'm not sure.

TechTV's Cat Schwartz posted cropped photos of herself on her blog that turned out to include embedded thumbnail previews which showed the original, uncropped pictures where she had posed topless. Here's how this mishap is explained:

"Photoshop generates small preview images for the pics it produces and hides them in the original image. If you change the image drastically, the preview thumbnail is changed too. But if you don't make a major change, and instead just crop the picture and resave it under the original file name, the preview thumbnail stays the same and reflects not what your image currently looks like but instead what the original looked like." [Link] Warning: PG-13 content

For the record, the author of this page is likely mistaken about at least one thing. It was probably the digital camera, not Photoshop, that embedded the thumbnail preview in the image.

Thumbnail previews are part of the EXIF metadata that all digital cameras embed into JPEG files. Incidentally, EXIF information and metadata is increasingly becoming a concern for professional photographers working in digital because it can potentially expose information (such as shooting conditions, or ...ahem... other things) that the photographer does not want to be revealed. However, using EXIF editing software, it's possible to strip out this embedded information. Photoshop's Save for Web command also strips out extra metadata and thumbnail previews automatically.

In addition, I was not able to reproduce this behavior in Photoshop 7 using my own digital camera photos. The site quoted above does not mention what version of Photoshop was used to crop these images (in fact, it's unclear whether Photoshop was actually used for the cropping), but it appears that this quirk has been corrected, at least in Photoshop 7.01. If you know what versions of Photoshop can reproduce this behavior, please use the discussion link below to post in the forum. I'm interested to know.

EXIF Information
Discussion

Also See: Too Much Information about hidden metadata in Microsoft Word documents from About Desktop Publishing.

[link via alphaChannel]