Writing JPG metadata, and image quality

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[Originally posted by haydnw on 2007-07-04 13:35:06-07]

I know that when you open and re-save a JPG, you lose quality each time due to the 'lossy' compression applied, and that this can lead to a degradation in image quality over a series of repeats.

Does writing the metadata in a JPG cause any change to the actual image data in the same way? Or is the image unaffected? It doesn't bother me in any serious way because I'm only doing it once and all my really important images are stored as RAW anyway. I'm just curious.  https://exiftool.org/forum/Smileys/default/smiley.gif" alt="Smiley" border="0" />

[Archive]

[Originally posted by exiftool on 2007-07-04 14:24:05-07]

Writing meta information with exiftool is lossless.  The
image data itself is simply copied over to the modified
file, byte for byte.  This applies to all image types: JPEG,
RAW, etc.

- Phil

[Archive]

[Originally posted by haydnw on 2007-07-04 18:40:50-07]

That's great, thanks very much.  https://exiftool.org/forum/Smileys/default/smiley.gif" alt="Smiley" border="0" />