When you first create a document or image, you will create a canvas that holds that image or document. The canvas size can be increased at any time to be larger or smaller than your current image. Follow the steps below to change the canvas size for your existing Photoshop document.
Instructions
1. Start Adobe Photoshop, and open a document that contains a canvas or image to which you would like to change the size of the canvas.
2. Choose the "Image" menu, and click on "Canvas Size" to open the "Canvas Size" dialog box.
3. Type a new size in the "Width" text box to change the width of the canvas. A higher size will increase the width, while a lower size will decrease the width of the canvas.
4. Type a new size for the canvas in the "Height" text box to increase or decrease the size of the canvas.
5. Change any other settings you would like to apply to the canvas, including anchor points or canvas extension color using the drop down menu, which is near the bottom of the "Canvas Size" dialog box.
6. Click the "OK" button to close the open dialog box and change the canvas size of the Photoshop document you have open.
