Photoshop Image Size vs Canvas Size

Image Size vs Canvas Size

Image Size and Canvas Size can be confusing. Let's look at them, their similarities and their differences.

Image Size

The actual dimensions (in pixels) of the entire image.

Image Size affects the content within the image. If you reduce Image Size, Photoshop resamples (shrinks) the pixels. If you increase Image Size, Photoshop resamples (enlarges) the image, which involves creating new pixels (which can lead to loss of quality).

Use Image Size when you want to resize your whole image — for printing, web, etc. For example, you have a 3000×2000 pixel image. If you change the Image Size to 1500×1000, the whole image will shrink.

Canvas Size

Canvas Size is the workspace area. It includes the image and surrounding area, such as borders.

It's like resizing the background paper behind your image. Canvas Size affects the space around the image — it doesn’t scale the image, it just adds or crops space. If you add space, you will see an area around the image. If you reduce space, the image will be cropped and you won't see all of it.

Use when: You want to add more room (or crop it) without changing the original content size. For example, taking the same 3000×2000 pixel image — if you change the canvas size to 4000×3000, the image stays the same, but you get more blank space around it (which you can fill with a background color). If you reduce the canvas size to 2000x1500 pixels, some of the image will be cropped.

Quick Summary:
Image Size = Resize the photo.
Canvas Size = Resize the frame.

Image Size and Canvas Size intially show the same details

If you open an image into Photoshop and then immediately look at Image Size and Canvas Size you will see that they are the same. In this case: 6.667 x 4.443 inches (@ 300 pixels per inch). Note that when you open Image > Canvas Size, it will show the details at the same resolution as Image Size. So if you want to change this, change it first in Image Size.

Increase Image Size and view in Canvas Size