Resize vs Resample in Photoshop
This article is about to go through the difference between resizing and resampling in Photoshop. So when we’re actually changing the size of an image in Photoshop there’s two ways you can go about it. You can either resize the image or you can resample it and a lot of people use those terms interchangeably but they actually mean different things and there’s quite an important difference between the two.
Now we will learn the difference between resizing our image and resampling the image. To do this will look at the Image Size dialog box at the top part in Photoshop.
Under Pixel Dimensions we have width and height and they are calculated in pixels. These numbers just directly correspond to how many pixels there are wide versus how many pixels there are high in the image.
In the Document Size below, this is where it gets a little bit trickier because in order to calculate the document size you need the width and the height plus the resolution. First of all let’s turn off the option of resample your image. As soon as you uncheck that you’ll notice that you cannot actually change the total pixel dimensions. All you can do is change the way that those pixels are distributed.
So now we can see that we could print this at 13 x 8 at 72 pixels per inch but 72 pixels print is a very low resolution. So you want to go ahead and switch this up to 300 pixels per inch so that you can print this image to your inkjet printer.
When you change it to 300 pixels per inch because you told Photoshop that it can’t add or subtract any other pixels with the option of resample image turned off. In this case, Photoshop had to use more pixels 300 of them per inch. Now we can print this image out to as large as it was at 72 pixels per inch.
Now if you click OK then you will notice that the size of the image in your preview area in the image didn’t change. This is because you’re not adding or subtracting any pixel now.
Original by Pixabay/ CC BY and edited by ClippingPathService
Let’s go back to Image to Image Size. This time we’re going to tell Photoshop to resample the image by turning it on. Now you can either resample the image up or you can resample the image down. Photoshop CS6 has one of the nice features in it and that is it will automatically pick the correct resampling algorithm. It will automatically choose Bicubic smoother if you make my image larger. It will choose Bicubic Sharper if you reduce the size of my image. So you want to make sure that you leave that on Bicubic Automatic.
Now if you wanted to print this image with a maximum width of 10 inches and you enter in 10. You’ll notice that this time that were in the image size dialog box because I have the option to resample image checked on I am actually taking away pixels.
The total size used to be 1.77M now it’s down to 1017.2K. You also had a lot more pixels in your width and height area. So, by returning on resample image Photoshop is allowed to take away or make up pixels.
If you wanted to print this 20 inches now we can see that Photoshop is actually going to have to add pixels. The file is used to be 1.77M now you told it that you need a file that is 69M. So Photoshop will automatically interpolate up or add pixels in order to give you this document size.
With 20 inches wide 13.3 inches high and a resolution of 300 pixels per inch. This time when you click ok you can see that your document actually got larger because Photoshop had to make up those additional pixels.
I’m going to undo that by choosing Edit and then undo image size just so that you can see the other direction as well.
If you go to Image and then Image Size and we decide that you only need to print this, let’s say- 6” x 4” of pixels per inch. As we have resample image turned on what used to be a 30M file is now going to be just a little over 6M.
When you click ok you can see that your file actually got smaller. So there you have it with the resample image option on in the image size dialog box you are allowing Photoshop to either make up pixels or throw them away. When you don’t have that keep on all you are telling Photoshop that it can do is redistribute those pixels at the resolution you specify in the width and the height in the document area of the image size dialog.
This is all about Understanding Resize and resample hope we made it easy to follow and understand.