carol.gimp.org

The first thing to note is TheGIMP will open the image at a viewable size. It does this without changing the file size, instead it changes the "resolution" of the view. TheGIMP simply zooms the view so that it will fit on your workspace. You can see the actual size in the title bar on the window. The image in this screen shot is actually 1008 pixels wide and 720 pixels long.

The titlebar also tells the mode of the image file. When working on an image with TheGIMP this should always read RGB. If your image says something else (Indexed or Grayscale), you should read the mode changing quickie and change it. You will see the difference in the quality of your changes.

Use the mouse and right click on the image. Follow the menu Image ->Scale Image.... When ever you click an option from the menu that has "..." behind it, expect a dialog. In this case, you should get the "Scale Image" dialog.

If you have a desired width, put it in the dialog at the top where it says "Width". 300 pixels is a nice width for web pages or email. After entering the number 300 into the Width box, the "Height" displayed will automatically change to the correct number which is 214 pixels for the sample image. It is best to only use one dimension when altering the image size like this, otherwise the image will become distorted (larger in one direction only). You can see the image that this scale dialog produced here.

Perhaps you want your image to look more like a 4 x 6 inch photo on most image rendering web browsers. Simply switch the units to "inches" and put "4" inches in the height box (opting for smaller than 4x6 inches rather than bigger). The transformed image should now look like a 4 x 6 inch photograph on most computer screens.

If you need for the image to be exactly a certain pixel size that is different than the size the dialog will automatically adjust itself to be, for example 200 x 200 pixels, use the dialog to scale the image so that one side is 200 pixels and the other side is larger than 200 pixels. This will leave some area to "crop" away (cropping is demonstrated in another "quickie"). The sample image scales to 200 X 280 pixels.

For demonstration purposes only, see the distortion that happens when you force the image to scale to an unconstrained size (without the cropping step). This frustrating fact about images on computers is shared with real printed photographs as well. It was just as difficult to make printed photographs or the film negatives fit into a pre-specified format. You can do this with computers, but you will distort the image.