Actually, you get almost no further degradation if you save the image
> again with the same settings that were used for the first save. The JPEG
> plug-in even stores information in the image when the image is opened
> and it will use that information to save it in the best possible way
> when you save it again. Just leave all controls at their default values.
> Note that I said "almost". Of course the image will suffer a little. But
> you won't get significantly better results if you increase the JPEG
> quality or change other settings in the save dialog. You just get a
> larger file.
Quality is relative to what you need, how the image is used as well. If
it's for internet use, 70% or so is reasonable quality. Image weight
adds up fast if you have a lot of large images. I don't do print media
so someone else would need to talk to it, but I commonly here that
300-600 dpi is requested whereas for the internet resolution is much
less of a factor.
If all I've been given is a .jpg I'll typically save it as a .png along
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