Shrinking jpegs!

[StewartTurner]

If I open a jpg image from my digital camera and click save in Photo Editor 10 the file size shrinks even though I have made no changes.

I think I have set things up to retain the highest quality in the saved jpg.

Am I losing image quality when I do this, and if so, how can I prevent it?

Thanks,
Stewart

[J_fike]

I no expert on this, but I believe the "100% quality" is misleading. I think it really means "save at the best quality jpeg is capable of", which means, since the jpeg format is lossy, there will be some loss in quality (I'm sure someone will correct me if I'm wrong.)

However, the way to avoid this is to treat your original image like a film negative. Store the original (archive it) and only copy it and then edit from the copy. If you write the original to a read only CD or DVD, that will automatically protect the file from being saved again. You can copy/download jpeg's all day and not lose any quality. But as soon as you save it, it forces the jpeg algorithm to do it's thing, which even at 100% quality is some file compression.

[StewartTurner]

But the original is a jpg too, so why is saving it in Photo Impact shrinking it further?

Your advice is fine for preserving the original but the reason I bought Photo Editor is to process images before printing, so naturally I want to preserve the quality of the processed image.

Stewart

[Xyzzy2]

But the original is a jpg too, so why is saving it in Photo Impact shrinking it further?

Because information was removed from picture twice- first when compressing in camera and then when saving in PI.

Your advice is fine for preserving the original but the reason I bought Photo Editor is to process images before printing, so naturally I want to preserve the quality of the processed image

Save in non-lossy format, like UFO, TIFF, PNG.

X

[StewartTurner]

OK, thanks.

[skier-hughes]

Yep, everytime you save a jpeg it compresses it. If you have a habit of making changes and saving often when working in case of a pc crash you may find your jpeg has ended up as a poor picture, so always save as mentioned above in a non-lossy format and if you want a jpeg save as this at the very end of the work.

[JenT]

And there is also the possibility that your camera's EXIF info is being stripped out of your resaved JPG, which would also make the file size smaller.

If the EXIF info is not important to you for printing, then as the others suggested, save a copy in a lossless format, such as UFO, TIFF, PNG or BMP make your changes on it and again, when you are ready to save the final image for printing, only then save as JPG.