Changing the canvas size allows you to add or remove pixels from one, two, three, or four sides of an image. Typically you will want to add pixels, to add room for type or to accomodate other images. Choose Image>Canvas Size. The dialog box will display the current size and then you can enter new height and width values; these are independent of each other. If you check the Relative box, then the sizes are relative to the original size of the image, i.e. positive values will increase, negative values will decrease.
The small square in the anchor area represents the location of the image in the new canvas and can be used to reposition the image in the canvas. Using the Canvas Extension Color menu, you can specify a color for the added pixels. If the original image contains layers but not a background, the additional pixels will be transparent.
Exercise: Add 100 pixels to the bottom of the flowers image using the color of the existing background.
Revised: October 20, 2018. Comments to Bill Pegram, wpegram@nvcc.edu
