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How to resize an image in Photoshop

How to resize an image in Photoshop
(Image credit: Hannah Rooke / Digital Camera World)

Knowing how to resize an image in Adobe Photoshop is a must-know skill for photographers and creatives. Luckily, it's really easy to do. The most common reason for needing to resize an image is to make the file size smaller but you may also need to change a file size so that you can print it.

Some of the best mirrorless cameras (opens in new tab) and best DSLRs (opens in new tab) have such high-resolution sensors that the file size of the images can be enormous. The Sony A7 IV (opens in new tab), for example, produces 123MB of uncompressed raw files which are absolutely massive. Not only would it take forever to process, but if you're uploading multiple images you’ll run out of space before you know it. 

• Read more: Best photo printers (opens in new tab)

It’s much easier to make an image smaller (known as downsampling) than bigger, as unwanted pixels can be thrown away. Making an image larger, however (known as upsampling) uses interpolation which basically means Photoshop creates new pixels. The downside to upsampling is that it can degrade your image quality and make your image appear very pixelated. The general rule is that you shouldn’t make an image bigger than it is straight out of the camera.

If you’re creating your first photography website, the chances are that you’ll need to resize multiple images at the same time. To do this you’ll need to learn how to batch resize which we will come onto later – you do it in the same way, only you can create an action for it so that you don’t have to do each one individually. 

So first, here's how to resize an image in Adobe Photoshop CC (opens in new tab).

How to resize an image in Photoshop

1. Open your image in Photoshop

First, you need to open your image in photoshop by going File > Open and select the image you want to resize. 

Once your image is open click on Image > Resize Image and make sure the ‘constrain aspect ratio’ is selected. This is important otherwise when you resize your image the aspect ratio will always change. Input how big you want your new image to be, you can input it in either cm, pixels, inches or points. 

(Image credit: Hannah Rooke / Digital Camera World)
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2. Check settings

If you want to increase the resolution of your image for print you will need to make sure the resample option is unchecked otherwise your image will be interpolated and the quality will degrade. You’ll notice that when you change the resolution of your image, the size of your image will decrease. This is because those same 72 pixels per inch are now having to cover 300 pixels per inch. 

How to resize an image in Photoshop

Note the difference in image size when you change the resolution from 300 DPI to 72 PPI (Image credit: Hannah Rooke / Digital Camera World)

3. Know your PPI & DPI

When referring to a digital image you use PPI which means pixels per inch whereas when you're talking about an image to be printed you use DPI which is dots per inch.

Once you’ve set the size of your image, checked the constraint crop is linked and he resolution is correct, Photoshop will show you how big your new file size is. Click ok to apply the changes. 

How to resize an image in Photoshop

The difference between an image viewed at 100% when it has been resized from 6000 x 4000 pixels to 2000 x 1333 (Image credit: Hannah Rooke / Digital Camera World)

4. Export your image

If you’re happy with the size of it you can click File ≥ Export > Save for web if you’re planning on sharing it online or export as if you want to print. Save for web will ensure it is saved as the smallest file possible with colors that are web-safe.

We'll be updating this article with many more methods for resizing your images. If you're looking for more Photoshop tutorials, check out these 100 editing tips (opens in new tab). If you haven't got Adobe Photoshop already, here's how to download it (opens in new tab).

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Hannah Rooke
Staff Writer

Having studied Journalism and Public Relations at the University of the West of England Hannah developed a love for photography through a module on photojournalism. She specializes in Portrait, Fashion and lifestyle photography but has more recently branched out in the world of stylized product photography. For the last 3 years Hannah has worked at Wex Photo Video as a Senior Sales Assistant using her experience and knowledge of cameras to help people buy the equipment that is right for them. With 5 years experience working with studio lighting, Hannah has run many successful workshops teaching people how to use different lighting setups.