I am getting really confused about scaling. I have scans at 600 dpi. I want to scale them so that they make good prints...about 300 dpi (or less?). I also need to scale them for display on line but so they can not be printed in a usable form...72 dpi (or less?).

I scale them in Gimp and the resolution changes also. Then I get real confused. Also, when I change the resolution in "print size" it does not change the resolution in "scale image". But if I change the resolution in "scale image" it does change the resolution in "print size".

Is there an easier way to grasp the process of scaling? And I am not even sure if I am talking about scaling or resizing. Aaaaa!!

Any really good tuutorials?

Let's see if I can confuse you further

Don't worry, someone will come along later with a link to a good description.

DPI stands for Dots Per Inch. It is only relevant to printing a physical copy of your picture and it will depend on the printing process you use if the settings you save in the image will be used at all.

When you are preparing pictures for the web the only considerations are the width/height in pixels (i.e. 1024 by 768) and sometimes the overall file size if you have storage and/or bandwidth constraints (How many megabytes etc). If you are concerned about image theft then consider adding a watermark as a fairly decent print can be made from a relatively small image - 600 pixel wide image printed 6 inches wide = 100dpi, which is a quite acceptable quality.

Am I correct to think that scaling an image changes the size of the image file and changing print size does not change the image but does add info to the image that tells the printer how to make the print?

Does scaling actually change the image or does it just adjust how it is displayed?
I notice that scaling does not change the dpi.

See what I mean? I need a dummies guide

Yes on both counts

It actually changes the image. If you scale down and then scale up to the original size, you'll get something blurry or blocky because you'll have lost information when scaling down.

The DPI for the printer is misleading anyway, since the printer uses a lot more dots per pixel than what you specify. A lowly inkjet printer will to 4800DPI but your eyes will never a notice anything past 600DPI.

I would use 72 dpi for web and 300 for printing both are standard usually.