2. Image > Image Size

3. The Image Size window will appear. Here you can adjust the settings. We will look through each setting in the next few steps

4. Constrain Proportions is a very important setting. Here is the official Adobe description

“To maintain the current ratio of pixel width to pixel height, select Constrain Proportions. This option automatically updates the width as you change the height, and vice versa.”

If Constrain Proportions is unchecked, then the height and width can be changed individually. By linking the width and height we can ensure that the image is not distorted when either the height or width is changed. As a general rule, we suggest having this option active.

To toggle this setting on and off, simply click on the chain icon (highlighted in the screenshot below)

5. Next up is Measurement. As a general rule, we suggest using pixels as your measurement. Working with pixel widths and heights is very common in Photoshop. If you would like to change to a different measurement, simply click on the drop down and select an available option.

6. Let’s take a quick look a Resolution. The resolution of your image is the finest of detail in an image and is measured by pixels per inch (ppi). The more pixels that are contained within your image, the higher the resolution. The resolution that you choose should be based on the project that you are creating.

Images for web – 72 Resolution
General Design work – 300 resolution
Print – 300+ Resolution

Images on the web are not displayed higher than 72 pixels per inch (ppi). So using a higher resolution just increase the image size, with no visual gain.

Change the resolution in the dialog box…

7. The final option is Resampling. Firstly, you need to know that there is a difference between Image Resizing and Image Resampling.

Image Resizing: Changing the size of the image, without changing the amount of pixels within the image.
Image Resampling: Changing the size of the image, increasing the amount of pixels within the image.

When you increase an image size, without resampling, the image will lose quality. This is because no extra pixels are added, even though the image size has increased. If you increase an image size, with resampling, then Photoshops algorithm will add in extra pixels for you, based on your image (thanks Photoshop!!!).

As a general rule, you should start your project at the correct resolution, then there will be no need for resizing. If you do need to resize, then leave this option as “Automatic” and let Photoshop do the work for you.

So now you have all the skills and the knowledge behind image resizing. You’ll likely use image resizing in most of you projects so it’s important to understand the nuts and bolts.

To help you visualize the process, we have changed our Image Size in the gif below. We reduced the height and width by 200px. Constrain proportions is active so as we changed the image width, the height automatically changed.