How to Resize an Image in Photoshop

Hi, everyone!

In this post, we’re mixing up a tasty cocktail of theory and practice on how to resize an image in Photoshop.

This is a skill you will use on pretty much on any Photoshop project you begin. We’ll start with some basic but fundamental concepts like pixels, resolution, and dimensions.

With the theory box checked off, we’ll jump into Photoshop so you can learn the tools and techniques to reshape your compositions into works of digital art. 

Grab your notebooks, bring your laptops, and let’s get to it!

Before We Start

This step-by-step guide is based on my Photoshop Advanced Training Course lessons. When you become a BYOL member, you gain access to this course as well as my 30+ additional courses on Photoshop, Illustrator, Lightroom, Premiere Pro, Webflow, and more. As a BYOL member you will also enjoy personalized support, earn certificates, and tackle exciting community challenges. Head here to sign-up! 

What is a Pixel?

What is a pixel? Have you ever zoomed into a photo until all you can see are tiny colored squares? A pixel is one of those squares. It’s the smallest measurable unit that can be displayed on your computer or mobile screen. Pixels can be joined together to form those images, shapes, text, or videos that you can find all around you.

Photoshop manipulates these little guys by adding and subtracting them or changing their color values until you reach the result you are looking for. It’s brilliant stuff, a whole universe shifting back and forth beneath your screen’s surface.

What is image resolution? 

Now let’s discuss resolution or pixel density. We know that higher resolution means more detail. But why does it work that way?

Resolution is measured in “ppi = pixels per inch” – or the number of pixels that combine in an inch to build, let’s say, an image. Have a look at this 5 x 5 inches photo of a flower, displayed at a resolution of 300 ppi. If we zoomed in on it, we’d count a first horizontal line of 1500 pixels. We could do the same on the first vertical line: 1500 pixels. If we do the math, we now know that there are 2.250.000 pixels holding this flower together, all shiny and full of detail.

What happens when we change the “ppi” value?

If we downsize it to keep its 5 x 5 inches, but displayed at a resolution of 72 ppi, we’d count 360 pixels horizontal and 360 pixels vertical, right? This means nly 129.600 pixels build up the image.

It’s a huge difference, right? Is this bad? Well, it depends on the use you have planned for it. If it’s meant to be something as small as a profile avatar for social media, it should be fine. What if you want to enlarge a certain detail to fit your composition or print it and hang it on a wall?

It’s a dimension thing!

Our flower’s dimensions were 5 x 5 inches (or 12.7 x 12.7 centimeters, 127 x 127 millimeters, etc.), but could be also measured by pixels: 1500 x 1500. A higher number of pixels in an image means you can change its dimensions with a lower loss of quality and detail. On the other hand, lower pixel numbers means more degraded (a.k.a. “pixelated”) results.

Resizing an Image vs Resampling an Image

Now that you have the basics down, what happens to pixels when we change the size of an image? To keep it simple, you can resize or resample an image. These two get confused a lot and both processes are usually called resizing – and Photoshop may be the reason for that, now. The difference lies in changing or not changing the number of pixels in it.

When you resize images, you don’t change the number of pixels in the image.

When you resample images, you ask Photoshop to change this number, by adding or subtracting pixels as you’re upscaling or downscaling it.

To keep this simple, let’s focus on resizing with help from the “Resample” option. It represents a huge evolution in Photoshop, making editing easier and more efficient. That’s why it must get front stage.

I don’t mention this distinction in my Photoshop Advanced Training course but I thought it could be a cool thing for you to know and – why not? – even impress a friend or two. 

Using what we’ve learned so far, we are ready to dive into resizing images in Photoshop! 

Timeout #1

We’ve been talking about image editing in Photoshop. Have you ever wondered what makes a photo editor great at his job? 

Step 1 – How to use the Image Size tool

This is where it all begins - your starting point for small adjustments or billboard enlargements. Let’s look at the options available and understand when you should use them.

Sample brief: We’ve got an image of a model and want to showcase this on a billboard, so we need to increase the image size.

Go to your top menu bar, select “Image” and then “Image Size” – for shortcut fans you can press Ctrl + Alt + I on PC or Command + Option + I on a Mac.

The Image Size window pops up and you’ll find some settings and an image preview that reflects the changes you are about to define. Before moving on, let’s have a quick look at what Photoshop hands out for you to do your powerful magic.

The first two items give you the information you need to begin with:

· Image Size: This is the image’s file size, the space it requires on your disk drive or cloud service. Remember that heavy file sizes demand higher performances from your computer, so it’s important to keep an eye on this. By the way, file size isn’t only affected by pixel dimensions! Consider other factors like file type, bit depth, number of layers, among others.

 · Dimensions: You know what this is, now – your image’s size in pixels. If you’re using your image on an online project, you’ll want to work with pixels. For printing, you will consider inches or millimeters, these are the values that printers and clients usually prefer.

Next, we find our settings:

· Fit to: These are some presets for common online and print solutions - they automatically redefine both dimensions and resolution and are great for daily and simple image editing.

· Width and Height: You can set up your desired image dimensions here, adjusting to different values, such as pixels, inches, points, percentage, etc. You won’t be using percentage much, it’s good for small adjustments based on simple math. See that link icon next to “Width” and “Height”? Click on it if you want to keep the image’s aspect ratio. It’s ok if you don’t, it always depends on your goal, but remember that you may end up with some distorted results.

· Resolution: We’ve seen this, too. Your image’s pixel density – and you know the more you have, the better it will look both printed or on screen. Relax, you don’t always need a large number for good results. For online use, you can usually shine bright with 72 ppi. In this project, we’re aiming for 300dpi or higher. 

· Resample: Remember resampling? This option controls how Photoshop works behind the curtain (by adding or subtracting pixels to your image) as it helps you keep maximum quality and detail. “Automatic” is, by default, everyone’s favorite, but understanding the other settings will make you a better designer, for sure, and give you a higher influence on your work’s outcome. We’ll check out its many possibilities further down the road. 

You also have a very useful preview window on the left that displays the changes you perform on your image as you make them. You can enlarge it by clicking and dragging from one of the windows’ corners. Amazing!

Step 2 – Width, Height, and Resolution

Now that we know what we can do with Image Size, let’s start transforming our photo into a marketing showstopper. Let’s work on its dimensions. 

Our sample brief is calling for a billboard, so let’s change the width from 2000 to 8000 pixels. See how the Height changed as well? This means our image is holding its aspect ratio constrained and our model won’t get all stretchy and funny in the end. Leave resolution at 300 ppi, we want to keep the pixel density high because this is going for print.

Step 3 – How to Resample in Photoshop!

This is what dreams are made of! Now we ask Photoshop to play with pixels by adding new ones (yes, it’s true!) or throwing away the ones you don’t need anymore. Real transformation begins now and you won’t even notice as it’s done in the blink of an eye. 

Make sure Resample is active by clicking on the checkbox. Automatic is there for speed, but these are all the selections available:

· Automatic: Pick this and Photoshop will do the choosing for you. Great for average enlargements and reductions, but tricky when you want to go big!

· Preserve Details (enlargement): The most common choice when you enlarge an image, as it also allows you to reduce noise and smooth up the result when necessary.

· Preserve Details 2.0: A good choice for enlargement, as Photoshop will handle pixels to keep the highest possible level of detail. It also allows for noise reduction.

 · Bicubic Smoother (enlargement): This is expected to deliver strong and smooth results when enlarging an image.

· Bicubic Sharper (reduction): Fit for sharp and detailed results on reduction resizing.

· Bicubic (smooth gradients): A smart option for sharper images or when Bicubic Sharper goes a bit too far.

· Nearest Neighbor (hard edges): It delivers fast but less precise results as this option acts by replicating nearest pixels to preserve hard edges.

· Bilinear: With medium-quality results, Bilinear adds pixels based on the average color of surrounding pixels.

Try adjusting your choice to the image you are resizing and consider how it is going to be displayed. One good call for one image may not be perfect for a different image. Try them all, if you must, and then decide which is best.

For our sample brief, let’s use Preserve Details (enlargement)”. This selection gives us an extra option, “Reduce Noise”. We can play around with it by clicking and dragging the marker left or right across the bar, make sure to check how the image changes on the preview and adjust until it feels smooth and natural.

Timeout #2

Take a quick break to learn about the importance of a photo editor’s work in the media industry and why even top photographers need to keep a close relationship with these “invisible” artists.

Step 4 – How to Use Multiple Views in Photoshop.

Want to speed up your workflow? You can compare multiple resampling versions at the same time, check every detail with no effort – or extra screen?

Go to your top Menu bar, select “Layer” and then “Duplicate Layer…”. A new window will pop up. On “Destination” click on the drop-down box and pick “New”. Name your new layer “Option 1” (or any other name you prefer) and click “OK”. Repeat twice for “Option 2” and “Option 3” .

You can now close the original. Let’s do it in a non-destructive way. 

You will end up with three open document tabs over your workspace. Repeat this guide’s steps 2 and 3 on all of them, picking one different Resampling option for each.

Now let’s compare them all at the same time!

Method 1 – The Skipping Stones

Cycle through the open documents with the shortcut Control + Tab on a PC or Command + Tab on a Mac.

Method 2 – The Gallery

Go to your top Menu bar, select “Window”, move to “Arrange” and click on “3-Up Vertical”. And there you have them!

Extra tips:

• You can move each image around by using your Hand tool (hold Spacebar and drag).

• You can align them all on the same point by setting up the first and then go to “Window”, move to “Arrange” and pick “Match All”.

• You can move them all at once by holding Spacebar + Shift and dragging . Incredible, right? This will help you observe all the differences between them and make the better choice for your image resizing.

Step 5 – Go for the winner!

After careful observation, you hold the best result as a winning prize.

This is it - we’ve covered the basics to image resizing or resampling. You now have a resized image with extra pixels to ensure that quality is preserved and all those nasty pixelated effects are completely gone. 

Reducing an image follows the same steps and, on most occasions, you get solid outcomes with hardly any trouble – resampling does wonders both ways!

What’s Next?

Take your photoshop skills to the next level in my course Adobe Photoshop Advanced Training. When you become a BYOL member, you gain access to this course as well as my 30+ additional courses on Figma, Photoshop, Illustrator, Lightroom, Premiere Pro, Webflow, and more. As a BYOL member you will also enjoy personalized support, earn certificates, and tackle exciting community challenges. Get started here.

See you in class! - Dan