Resizing the canvas
The image canvas is the work area of the image and defines the image dimensions — for example, 200 × 300 pixels. If you need more space to add elements to an image, you can increase the canvas size, or you can resize the canvas to make it smaller.
If you want to resize by adjusting the image size, see
Resizing images.
What is the difference between reducing the canvas size and cropping an image?
Reducing the canvas size is not always the same as cropping an image. For images with layers, reducing the canvas size does not delete the pixels outside the new canvas area — it just shows less of the layer. Background layer information is always deleted, even when there are other layers in the image.
To change the canvas size
Edit workspace
1 Choose Image Canvas Size.
The Canvas Size dialog box appears.
2 In the New Dimensions group box, mark the Lock aspect ratio check box.
3 Set or type values in the Width and Height controls.
4 In the Placement group box, click a button to set the placement of the image in the new canvas, or set values in the Top, Bottom, Left, and Right controls.
The values show the amount of canvas added or subtracted from each edge.
5 Click OK.
If you increase the canvas size, you can choose a color for the added canvas area by clicking the Background box and choosing a color.
You can resize the height and width independently by unmarking the Lock aspect ratio check box, and setting values in the Height and Width controls.
You can change the units of measurement for the border by choosing an option from the drop-list in the New Dimensions group box.