What does ExifTool's 'minor: Error reading PreviewImage' warning mean for JPEG files?

Asked 10/17/2015

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When sorting JPEGs with ExifTool using -directory<EXIF:DateTimeOriginal, some files produce this warning:

Warning: [minor] Error reading PreviewImage from file

The affected files mostly came from a smartphone and an Olympus camera, and there were no obvious transfer problems. Does this warning suggest image corruption, or is it usually just an issue with the embedded preview metadata? Should I be concerned about the long-term integrity of the photos?

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

11y ago

2 Answers

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Unless you have need of the PreviewImage, it probably isn't worth worrying about. Minor errors aren't necessarily a sign of image damage. It could be that the camera isn't writing the image metadata exactly according to the specifications or that ExifTool doesn't deal with the peculiarities of that specific camera. Given the huge range of cameras out there, both situations happen fairly frequently.

If you feel the need, you could head over to the ExifTool forums and post an example image. Phil Harvey, the creator of ExifTool, is quite likely to take a look at the image and figure out what the problem is and if need be, will quickly update ExifTool to deal with it.

Originally by user37960. Source · Licensed CC BY-SA 4.0

user37960

11y ago

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AI Answer

Generated from our catalog & community — verify before relying on it.

Usually this is not something to worry about. The warning is specifically about the embedded PreviewImage metadata, not necessarily the main JPEG image data.

Because ExifTool marks it as a minor warning, it often means one of these things:

  • the camera/phone wrote metadata in a slightly non-standard way, or
  • ExifTool doesn’t fully handle that particular metadata variation yet.

With the wide variety of cameras and phones, both cases happen fairly often and do not automatically mean the image itself is damaged.

If the photos open and look normal, and you don’t need the embedded preview, the warning is usually safe to ignore.

If you want to investigate further, the best next step is to post a sample file on the ExifTool forum. The ExifTool author is known to review examples and may identify whether it’s harmless metadata oddness or something that needs a software update.

UniqueBot

AI

11y ago

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