The fastest way to resize your canvas

Open your image in Photoshop, then go to Image in the menu bar and select Canvas Size. A dialog box will appear showing your current width and height in pixels (or whatever unit you have set). Type in your new dimensions, choose where you want your image positioned on the new canvas, and click OK. That is the complete process.

The canvas is the background workspace your image sits on — changing it does not crop or shrink your actual image the way resizing does. If you make the canvas larger, you get empty space around your image. If you make it smaller, parts of your image may get cut off unless you reposition the image first.

Key Takeaways

  • Canvas Size is found under Image in the menu bar and lets you add or remove space around your image without changing the image itself.
  • The anchor grid in the Canvas Size dialog shows you where your image will sit on the new canvas — click a different square to move it.
  • You can set canvas size in pixels, inches, centimetres, or other units by clicking the dropdown next to the width field.
  • If your new canvas is smaller than your image, parts of the image will be hidden or cut off depending on where you anchor it.

Understanding the Canvas Size dialog

When you open Canvas Size, you see two main sections: the current dimensions and an anchor grid. The width and height fields show your existing canvas size. Below that is a small grid with nine squares — this is your anchor point, and it controls where your image sits on the new canvas.

If the center square is selected (the default), your image stays centred when you change the canvas size. If you click the top-left square, your image will be anchored to the top-left corner of the new canvas, leaving empty space on the right and bottom. This matters most when you are making the canvas larger and want the image in a specific position.

You can also set the canvas colour — the empty space that appears when you enlarge the canvas. Click the colour swatch next to Canvas extension colour to choose a background colour for that new space.

Changing the unit of measurement

By default, Photoshop shows canvas dimensions in pixels. If you need to work in inches, centimetres, or another unit, click the dropdown menu next to the width field (it usually shows "px"). Select your preferred unit from the list.

This is useful if you are preparing an image for print and need specific physical dimensions. For web images, pixels are standard. For print, you might work in inches or centimetres and set a specific resolution (DPI) to may support quality.

Making the canvas larger

Increasing canvas size adds space around your image without changing the image itself. Type larger numbers in the width and height fields. The anchor grid determines where your image sits on that larger canvas — if you want it centred, leave the center square selected.

The new space fills with your chosen canvas extension colour. If you have not set a specific colour, Photoshop uses the current background colour in your toolbox. You can paint on this new space, add text, or leave it transparent if you flatten the image later.

Making the canvas smaller

Reducing canvas size crops away the edges of your image. Before you do this, reposition your image using the anchor grid so that the parts you want to keep stay visible. If you anchor to the top-left and then shrink the canvas, the bottom and right edges will be cut off.

Photoshop will warn you if the new canvas size is smaller than your image — it will ask whether you want to proceed. Click Proceed to continue. The hidden parts of your image are not deleted; they are just hidden. You can undo the change or increase the canvas size again to reveal them.

Centering your image on a new canvas

If you have already changed the canvas size and your image is not where you want it, use the Layer menu and select Align to access alignment tools. You can also manually move the image layer using the Move tool (press V) and drag it into position.

To centre an image on a larger canvas after the fact, go to Image, then Canvas Size again. This time, select your image layer in the Layers panel first, then use Layer > Align Layers to Selection > Centres to centre it automatically.

Flattening and saving after canvas changes

Once you have resized the canvas and positioned your image, you can flatten the image if you no longer need separate layers. Go to Image and select Flatten Image. This merges all layers and fills any transparent areas with the background colour.

Save your work using File > Export As (for JPG, PNG, or other formats) or File > Save As (to keep it as a Photoshop file). Canvas changes are not permanent until you save, so you can always undo and try different dimensions.

Frequently Asked Questions

Does changing canvas size crop my image?

Only if you make the canvas smaller and your image extends beyond the new boundaries. Making the canvas larger adds space around your image without removing anything. You control what gets hidden by using the anchor grid.

Can I undo a canvas size change?

Yes. Press Ctrl+Z (Windows) or Command+Z (Mac) when ready after the change, or go to Edit > Undo Canvas Size. You can undo multiple steps using the History panel if needed.

What is the difference between canvas size and image size?

Canvas Size changes the workspace around your image without altering the image itself. Image Size (also under the Image menu) actually resizes the image content, which changes its dimensions and can affect quality. Use Canvas Size to add borders or space; use Image Size to scale the image up or down.

Why does my new canvas space look transparent instead of coloured?

Your layer may not have a background. If you are working with a layer that has transparency, the new canvas space shows as transparent (a checkerboard pattern). Flatten the image or fill the transparent area with colour using the bucket fill tool to make it solid.

Can I set canvas size to specific print dimensions?

Yes. Change the unit dropdown from pixels to inches or centimetres, then enter your desired print size. Make sure your image resolution (found in Image > Image Size) is set to at least 300 DPI for print quality.