Does size reduction in a fine quality JPEG photograph introduce noise?

Question

Does size reduction in a fine quality JPEG photograph introduces noise?

I use Gwenview to reduce the size of the JPEG photographs. Does that cause some noise introduction?

Asked by Anisha Kaul

Answer

In essence, no. That is, if you are referring to grain like noise such as what you see with higher ISO images. What you have with saving/resaving jpegs (especially at diffrerent quality levels) is artifacting. You can read about it here: http://en.wikipedia.org/wiki/Compression_artifact. The more aggressive the compression with jpeg the more data is thrown away (as mentioned in the earlier answer) and thus more visual artifacts are created.

I'm not familiar with the tool you mention but the best thing is use a higher quality setting (if available) for images that have lots of smooth areas (as those tend to be areas that get artifacts) or for ones with lots of detail you want to make sure is in the final image.

Answered by nwcs

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