Change the image size
Learn how to resize an image, crop and straighten, and add to the image canvas in Adobe Photoshop.
Published
1 Resize an image
Change the size of an image.
Introduction
Let's talk about how to change the size of an image in Photoshop CC.
I suggest that you start with this image from the downloadable practice files for this tutorial.
I'd like to set the size of this image, so that it's a good fit for posting to a particular website, where I happen to know, that the ideal image size is 900 pixels wide.
Checking the original image size
Before we resize this image, let's check how big it is to start with.
In most cases, you'll want to start with an image that's bigger than or at least not a lot smaller than the resized image that you need.
That's because, if you enlarge an image a lot, at some point, it can start to look blurry.
I'll go down to the status bar at the bottom of the Document window, and I'll click and hold on the document size information.
In the small window that pops up, we can see that this file is 1800 pixels wide by 1200 pixels high.
Since we want to put it in a spot that's only 900 pixels wide on our website, that means we'll be scaling it down.
To resize this image,
Opening the image size dialog
I'll go up to the Image menu, and I'll choose Image Size...
That opens the Image Size dialog box.
If you like, you can make this window bigger by going to the bottom right corner and dragging out.
Over on the left, you can see a preview of the image and on the right, are the controls for changing image size.
There's a lot of information here, but you don't have to work through all of it, particularly when you're resizing an image that will be viewed on the screen as opposed to print.
As we are in this example.
So, there's just a couple of things to check here.
Understanding key resize settings
First, make sure that this Link icon is on.
This is what it looks like when it's on.
If I click it, this is what it looks like when it's off.
So, we want it on, to make sure that the Width is linked to the Height, so that when we resize the image, the original proportion of width to height is preserved and the image doesn't look squeezed or stretched.
Second, make sure that there's a checkmark in this box, the Resample box.
When this box is checked, you're telling Photoshop CC that it's OK to throw away some pixels when it makes this image smaller.
Or if you were making the image bigger, to add some pixels.
And third, take a look over to the right of the Width and Height fields, where you can see the unit of measurement that's being used to report the dimensions of the image.
By default, this is set to inches.
But when you're sizing an image for use on-screen as we're doing in this example, the correct unit of measurement is not inches, it's pixels.
So, I'm going to click on either of these 2 menus, and change it from Inches to Pixels, and the other menu changes too because the Width and Height are linked.
Now it's time to change the size.
Resizing the image for on-screen use
I'll go to the Width field and instead of 1800 I'll type 900.
You can see that the Height field automatically changed, and it changed proportionately.
Now, here's a bonus tip: if you wanted an image to have different proportions, say 900 by 400, rather than 900 by 600 in this case, the best way to achieve that would be to use another tool, the Crop tool, which we're going to cover in another movie.
Before I click OK, you may be wondering why I didn't change the Resolution field.
That's because this Resolution field is only relevant when you're preparing an image for print.
When you're sizing an image for on-screen use, as in this example, the number in this field really doesn't affect the dimensions of the image.
So, you can leave it set to whatever it happens to be.
So, after making those few changes in the Image Size dialog, we can now come down to the OK button and click there to close the Image Size dialog box and take us back to the Document window.
If you like, you can go back to the Status bar and check the size of the resized image.
I'll click and hold on the information there and you can see that we now have a 900 by 600 pixel image instead of the original which was 1800 by 1200.
All that is left to do, is to save the image.
Saving the resized image
I'll go up to the File menu, and I'm going to choose Save As... rather than Save because I don't want to save over the original 1800 by 1200 pixel version.
So, in the Save As dialog, I'm going to give this version another name.
You can type anything you want here.
I'm going to type "Resize-web.jpg" for my web sized version of the file.
I'll leave everything else as it was and I'll click Save.
I'll click OK in the JPEG options window, and now we're done.
So that's how to resize an image for on-screen use in Photoshop's CC Image Size dialog box.
What you learned: To resize an image
Choose Image > Image Size.
Measure width and height in pixels for images you plan to use online or in inches (or centimeters) for images to print. Keep the link icon highlighted to preserve proportions. This automatically adjusts the height when you change the width and vice versa.
Select Resample to change the number of pixels in the image. This changes the image size.
Click OK.
2 Set the resolution
Change the resolution of an image.
Introduction
If you like to print images, it can be useful for you to have a basic understanding of what image resolution means in Photoshop CC, and how to change the resolution of an image to prepare it for print.
That's done in the Image Size dialog box.
If you're following along, let's open this image, that you'll find in the practice files for this tutorial.
And then go up to the Image menu, and choose Image Size...
In the Image Size dialog box,
Understanding image size and resolution for print
you can see the Dimensions of this image reported in pixels.
When an image is still on your computer, that's how we measure its size, in pixels.
But if we were to print this image, we would measure the size of the print in inches, not pixels.
Down here in the Resolution field, you can see the resolution that's currently set for this image, it's 100.
There's nothing special about a resolution of 100, it's just a round number that I picked when I set up the file for this lesson.
Now, what does Resolution mean here?
Well, if you read across this line from left to right, you may get a sense of it.
This is telling us that resolution is a particular number of Pixels/Inch, in this case 100 Pixels/Inch.
Another way to say that, is that if and when you print this image, 100 pixels out of the total 1800 across and the total 1200 down, will be assigned to every printed inch, horizontally and vertically.
Now if you don't like math problems, you can skip the next part, but if you like to think of this in terms of math, here's a simple example.
So, the math problem is: divide 1800 by 100
How pixels, inches, and resolution relate
and you get 18.
That means that at resolution of 100 pixels per inch, this file will print at 18 inches across.
And it works the same way vertically.
If we divide the total, 1200 pixels of height into groups of 100, that gives you 12 groups or 12 inches.
So, the height of the printed image will be 12 inches.
So, if you understand that basic concept, now you're probably wondering, well what's the best number to put in the Resolution field when you're preparing an image for print?
Unfortunately, there's no one answer because that depends on what printer you're using.
But assuming you're printing at home on a typical inkjet printer, it's fair to say, that a resolution of about 300 pixels per inch will do.
If I were to print the image with only 100 pixels per inch, it might look OK, but if you got really close to it, it wouldn't look its best.
Because my desktop inkjet printer really needs around 300 pixels per inch.
So how do you go about changing the resolution of a printed image
Choosing the right resolution for printing
to 300 pixels per inch in this dialogue box?
Changing resolution without resampling pixels
The first step is to make sure that the Resample box is unchecked.
Because if we're just changing the resolution, we probably don't want to change the total number of pixels in the file.
And that's what Resample does.
So, let's say that we want the total number of pixels in the file to remain at 1800 by 1200.
We just want to reallocate them into groups of 300 rather than groups of 100.
So, what I'm going to do is type 300 in the Resolution field.
Spoiler alert: when I do that, the number of inches in the Width and Height fields will change too.
So, let's go ahead and type 300 here.
And sure enough the Width and Height have changed from 18 inches and 12 inches, to 6 inches by 4 inches.
And that's the size at which this image will print
Final print size and saving the image
with the necessary resolution to make the best print.
I'm done here, so I'm going to click OK.
That closes the Image Size dialog box and takes me back out to the Document window.
And here I have an image ready to save and print at 6 inches by 4 inches, with 300 pixels in every inch.
What you learned: To change image resolution
Choose Image > Image Size. Resolution in this dialog box means the number of image pixels that will be assigned to each inch when the image is printed.
Leave width and height set to inches for printing.
Deselect Resample to preserve the original number of image pixels.
In the Resolution field, set the number of pixels per inch to 300 for printing to a typical desktop inkjet printer. This changes the number of inches in the width and height fields.
Click OK.
3 Crop and straighten an image
Use the Crop tool.
Introduction
The Crop tool is one of Photoshop's CC most useful tools, particularly for those of you who take lots of photographs.
You can use it to improve a composition and to straighten crooked photos.
I've opened this photo from the practice files for this tutorial.
So, I can show you the basics of the Crop tool.
I'll start by selecting the Crop tool here in the Tools panel.
Reframing a photo with the crop box
As soon as I do, you can see this border around the whole image.
That's the Crop box.
I'll move my cursor over any of the corners or any of the edges of the Crop box and drag to reshape that box.
So, in this case, I might drag it way in to create a very different composition than the original photograph.
As you create your crop, Photoshop CC shows you a preview with the areas to be cropped away shaded in gray.
That way you can evaluate what it is you're about to eliminate before you finalize the crop.
Now, before I finalize this crop,
Using non‑destructive cropping options
I want to go up to the Options bar to show you an important option there.
And that is Delete Cropped Pixels.
That option is checked by default.
I usually like to uncheck that.
Because when Delete Cropped Pixels is checked, if you finalize the crop and save the image, you'll permanently delete the cropped away pixels.
But, with this option unchecked, you can bring back the cropped away pixels at any time.
Let's give it a try.
I'm going to finalize this crop by going over to the big Checkmark in the Options bar and clicking there.
Now, there are other ways to finalize a crop, but I like this way because it's very simple.
So now you can see the photo with the crop applied.
Let's say that I'm doing something else with the image and then, I change my mind about the way I'd cropped it.
At any time, I can go back and select the Crop tool and then click on the image again, and all the pixels that I cropped away appear back in view and I can change my crop.
This time I might include some of those cropped away pixels.
By the way, you may have noticed that there's a grid
Improving composition with the rule of thirds
of vertical and horizontal lines on top of my photo as I use the Crop tool.
This overlay presents a classic compositional technique known as the rule of thirds.
The idea of this technique is that if you place the important content in an image at the intersection of any of these horizontal and vertical lines you may improve the composition.
Let's give it a try with this image.
I'm going to place the bouquet right at this intersection by clicking on the image and dragging and placing it here.
And then I might reshape the crop boundary a little more, pulling it in tighter on this bouquet.
And then I'll click the Checkmark.
Again, I'm going to click on the image with my Crop tool to try to fine-tune this crop a little more.
I notice that this image is a little crooked, especially down here at the table.
Straightening crooked photos with the crop tool
One of the things you can do with the Crop tool is straighten an image.
There are a couple of ways you can do that.
You either can move your cursor outside of one of the corners and manually try to drag to straighten the image, and this grid appears that helps you do that.
I prefer the automatic method.
So, I'm going to undo, that's Command + Z on the Mac, Ctrl + Z on the PC.
So, the image is crooked again and then I'll go up to the Options bar and I'm going to use the automatic straighten tool.
I'll click on that tool to select it in the Options bar for the Crop tool.
I'll move into the image, and then I'm going to click along the edge of this table, hold my mouse down, and drag a little way further along that edge.
Now you don't have to go all the way along with the edge.
Sometimes just a little bit will do the trick, like this.
And Photoshop CC uses your line as a guide to rotate the image so that the content looks straight.
I'm going to fine-tune this crop a little more, maybe bringing up this edge and maybe moving the bouquet over a bit to put it right in the center.
And then I'm going to go up to the Options bar and click the Checkmark to finalize my crop.
So those are some of the basics of the Crop tool.
I hope you give these techniques a try to work on your own compositions in Photoshop CC.
What you learned: To crop and straighten an image
Select the Crop tool in the Tools panel. A crop border appears.
Drag any edge or corner to adjust the size and shape of the crop border.
Drag inside the crop border to position the image inside the crop border.
Drag outside a corner of the crop border to rotate or straighten.
Click the check mark in the options bar or press Enter (Windows) or Return (macOS) to complete the crop.
4 Expand the canvas
Add some space to the document canvas.
Introduction
There may be times when you want to add to your document canvas, so there's more room to add elements like text or images to your design.
You can do that by using the Canvas Size command which we'll look at in this lesson.
If you're following along, you can use this image from the practice files for this tutorial or an image of your own.
To add to the canvas around this image,
Understanding canvas size versus image size
I'll go up to the Image menu, where there is a Canvas Size... command right below the Image Size... command.
Now, just to keep these 2 straight, the Image Size command..., which we looked at in another video in this tutorial, works differently than the Canvas Size... command.
Unlike Image Size..., Canvas Size... doesn't change the size of your actual photos or other artwork or images in a composition.
It just lets you add space around those items.
So, let's select Canvas Size...
And that opens the Canvas Size dialog.
At the top of this dialog, you can see the Width and Height of this image in Inches.
Expanding the canvas using relative pixel values
And down here you can add to the Width of the canvas or add to the Height of the canvas or both.
And those fields are set to Inches by default also.
But when you're preparing an image for online use, rather than for print, it makes more sense to change this unit of measurement to Pixels because that's the way we measure and talk about the size of images on screen, as you learned earlier in this tutorial.
So, I'm going to change either one of these menus from Inches to Pixels.
And the other menu changes too.
If you know the total width in pixels that you want the image to be after expanding the canvas, you could type that number here in the Width field.
But it's often easier to just tell Photoshop CC how many pixels to add to the canvas without worrying about what the total will be.
To do that, come down here and click the Relative checkbox.
That sets the number in the Width and Height fields to 0.
And now, I can type in the number of pixels that I want to add to the canvas.
So, let's say that I want to add 400 pixels to the width of the canvas.
I'll type 400 here.
If I wanted to add to the height of the canvas, I could do that too.
I'm just going to leave that at 0 for now.
And then I'll click OK to apply that.
And out in the Document window, you can see that Photoshop CC added canvas to both the left and the right sides of this photo.
What it did was split the 400 pixels of extra width that I asked it for, into 200 pixels on the right and 200 pixels over here on the left.
Well, what if I wanted to add canvas to just one side of this image.
Adding canvas space to a specific side
Let's say over here to the right side.
That's done slightly differently.
So, let's undo what we've done so far, try that instead.
I'll press Command +Z on the Mac, Ctrl + Z on a PC to undo.
And I'll go back to the Image menu and choose Canvas Size... again.
The first thing I'm going to do here is to check that the Width and Height fields are still set to Pixels.
And they're not, they've reverted to the default Inches.
So again, I'll change those menus to Pixels.
And I'll double check that Relative is checked.
As I said, I want the added canvas to appear just on the right side of this image.
To do that, I'll go down to this anchor diagram and I'm going to click on the middle box on the left side of this diagram.
What that does is tell Photoshop CC to pin or anchor the image to the left side of the canvas, and put the extra canvas to its right.
So now I'm going to go up to the Width field, and I'm going to type in the number of pixels that I want to add to the right side of this image.
Let's add 800 pixels.
And click OK.
And that's exactly the effect that I wanted.
Choosing canvas extension color and transparency
You probably noticed that so far, my canvas extensions have all been white.
But you can control the color of your canvas extension, here in the Canvas Size dialog, using the Canvas extension color menu here.
By the way, if you're working on another image, and you're not on a special background layer, as we are in this image, then your Canvas extension color menu will be unavailable and the canvas that you add will be transparent.
It will appear like a gray and white checkerboard in Photoshop CC.
I'm just going to click Cancel.
And, if I want to save this image,
Saving the image with expanded canvas
I'll go to the File menu and I'll choose Save As..., so I don't save over my original.
So that's how you can add space to your document canvas, so you have some extra room to add more image elements.
What you learned: To change canvas size
Choose Image > Canvas Size
To add a canvas, enter the amount of width and height to add. Measure width and height in pixels for online use or in inches for print.
Select Relative, and then select an anchor point in the canvas diagram. The arrows point to the sides where the canvas will be added.
Click OK.
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