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The photos on my computer seem to have degraded in quality since having been uploaded to my computer, and would sometimes have a flickering strobe effect, which would disappear if I restarted the computer. Can bit rot be responsible for this?

  • Possible duplicate of Is there a tool to check the file integrity of a series of images? – mattdm Oct 1 '18 at 20:07
  • Suggested duplicate answers the title problem, but not "could this be caused by?" question – mattdm Oct 1 '18 at 20:07
  • The photos on my computer seem to have degraded in quality since having been uploaded to my computer, How are the images transferred to your computer (i.e., are they smartphone images synced via cloud services such as Google Photos, Apple Photos, etc., or is your camera connected via USB, or are you inserting the memory card into your computer)? Are you using image editing software to manage the transfer process (such as software that came with your camera, or Lightroom, etc.)? After transfer, is there any software that is automatically adjusting or "optimizing" your photos for storage? – scottbb Oct 1 '18 at 20:22
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No. Even the tiniest (one bit) change to a typical JPEG image produces a huge change in the output due to the compression methods involved - you can see some examples in the data degradation article on Wikipedia. It certainly never produces a gradual reduction in human-perceived image quality.

What you're describing, particularly the "flickering strobe" effect, means your monitor / laptop screen is on the way out.

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Bit rot occurs at the hardware level when a bit is unstable and flips. The consequence at the filesystem level is corrupt data. You would know bit rot has occurred when you see corrupt files appear. When the frequency of corruption increases, it is past time to replace the storage medium in question.

Corrupt images tend to be obvious. If degradation of image quality appears gradual or difficult to perceive, another cause is likely.

  • You use software, such as a photo editor or manager, that alters images.

  • You use a cloud service, such as Google Photos, that recompresses images.

  • Your phone resizes or recompresses the images prior to transfer. This is especially common with iPhones.

  • Enough time has passed since transferring the files that your memories of image quality do not match that of the actual images. Technology has improved significantly over the years so that what was once considered "good" quality is now no longer anywhere close.

The photos... would sometimes have a flickering strobe effect, which would disappear if I restarted the computer.

Images do not flicker. Flickering is strongly indicative of a hardware problem associated with video output. Some possible causes:

  • Recent video driver update.
  • Changed video output settings, such as refresh rate.
  • Damaged or low-quality video cable.
  • Problem with monitor, such as failing fluorescent backlight.
  • Unreliable power source, such as failing power strip or UPS, causing brownouts.

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