I take photos on my Canon (It happens on both my Canon EOS Rebel t1i and my Canon EOS R) camera then download them onto my iPhone. Then when I zoom in close enough, there are these invisible lines on the image (when you follow them along they form a 3x3 grid on the image).This happens in every single image that I download from my camera to my iPhone. What are they, and if possible, how can I fix them?



Half-Way Zoomed In:

Half-Way Zoomed In

Fully Zoomed-In:

Fully Zoomed-In

  • \$\begingroup\$ Are you shooting RAW or JPG? A 3x3 pattern sounds like it could be related to whatever demosaicing algorithm is in use, although with the typical Bayer filter, I would expect more of a 2x2 or 4x4 tiling... \$\endgroup\$
    – twalberg
    Commented Oct 16, 2020 at 19:46
  • 2
    \$\begingroup\$ Your original image has obviously been resized and is not an original. It would help to see the actual original. \$\endgroup\$ Commented Oct 16, 2020 at 22:28
  • \$\begingroup\$ Are these line visible before the image is resized? \$\endgroup\$
    – Michael C
    Commented Oct 16, 2020 at 23:03
  • \$\begingroup\$ I’m shooting in RAW \$\endgroup\$
    – user95469
    Commented Oct 18, 2020 at 15:13
  • \$\begingroup\$ The lines are not visible before the image is resized. \$\endgroup\$
    – user95469
    Commented Oct 18, 2020 at 15:14

1 Answer 1


The only lines I see are JPEG block artifacts. They typically occur along 8x8 pixel boundaries when images are compressed with low-quality settings. Solutions depends on when they are introduced to the image.

  • If introduced by the camera, use higher resolution and quality settings. ("Fine")
    • If you are resizing or otherwise processing images prior to transfer, you can try higher resolution and quality settings.
  • If introduced during transfer to the iPhone, change the transfer settings or method used to transfer.
  • If introduced after transfer to the iPhone, find the offending app and change its settings or remove it.
    • Do you have iCloud backups enabled? Is it set to remove images to save space? Is it saving original or compressed images?

artifacts marked

  • \$\begingroup\$ The problem is that JPEG block artifacts are usually more pronounced in the fully zoomed out image why doesn’t that happen in my case. \$\endgroup\$
    – user95469
    Commented Oct 20, 2020 at 1:58
  • \$\begingroup\$ @LiamMcDaniel It might help if you can put the raw files somewhere for others to download and look at to see if the lines you're referring to are present in the original. \$\endgroup\$
    – xiota
    Commented Oct 20, 2020 at 2:07
  • \$\begingroup\$ I have since cleared the originals of that particular photo off of my camera. \$\endgroup\$
    – user95469
    Commented Oct 20, 2020 at 15:03
  • \$\begingroup\$ I don't think that it is the camera, I think that if I compressed the RAWs with canons in camera RAW processing it would be fine. \$\endgroup\$
    – user95469
    Commented Oct 20, 2020 at 15:04

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