How to resize an image for printing

Image resizing involves altering the dimensions to make an image smaller or larger, which in turn affects the number of pixels and the image's overall quality. When you resize an image, you're changing the DPI and resolution of the image, so that it has more or less pixels to fit a specific frame or print it in a certain size. 

So, when you add or remove pixels from an image, depending on the size of the photo print it will be in, it will make the image sharper, clearer, and more vibrant - overall improving the quality of your image and photo print. 

What is the difference between resizing and cropping an image?

Where resizing is changing the amount of pixels and the entire dimensions of your image, cropping is simply cutting parts out of it. Cropping can allow you to improve the composition, focus on a specific subject, or achieve a certain shape for the image, but it won’t necessarily improve the quality of the image - this is the pixels’ job. 

Whether they’re prints to go into a family photo album or to frame as a gift, you want your images to be vibrant and clear. The problem is that that isn’t always the case when you go to print it. 

Depending on your camera, your photograph will be taken at a certain DPI and resolution. However, the photograph taken isn’t always perfect for the size of photograph you want to print, and if the resolution is too low, your image may come out blurry or pixelated. 

When you enlarge an image, the pixels typically stay the same. If it is enlarged too much, the individual pixels become visible to the human eye - resulting in a blurry or pixelated, low-quality photo print. 

So, to improve the quality of an image before you print it, you may need to resize the image, which means changing the DPI and resolution of the image. Whilst this may seem super complicated, with the right knowledge, it is super easy to fix!

When should you resize images for printing?

You shouldn’t need to resize every photo before you print them. However, if you’re concerned about the quality of the image once it is printed, it is best to check the DPI and resolution beforehand to ensure it will be perfect for the size of print you’re after. 

However we will always recommend resizing your images if you’re enlarging images - especially to poster prints - or if you’re making physical copies of restored photographs. Resizing will allow you to sharpen the image, remove any blurry or pixelated aspects, and result in a high-quality print.  

Now that you know what image resizing, DPI and resolution is, and both why and when you may need to resize your images for photo printing - what are the dimensions needed for standard photo print sizes?

As mentioned earlier, 300 DPI is generally recommended for all high-quality photo prints, and resolution is calculated by multiplying the DPI by the print size in inches. 

However, if you don’t have a calculator to hand, or need some quick answers, you can find all the information needed below: 

6x4” photo prints

DPI: 300
Resolution: 1800 x 1200 pixels 
Aspect ratio: 3:2

7x5” photo prints

DPI: 300
Resolution: 2100 x 1500 pixels
Aspect ratio: 3.5:2.5 

8x6” photo prints 

DPI: 300
Resolution: 2400 x 1800 pixels
Aspect ratio: 4:3

10x8” photo prints

DPI: 300 
Resolution: 3000 x 2400 pixels 
Aspect ratio: 5:4

12x8” photo prints

DPI: 300
Resolution: 3600 x 2400 pixels
Aspect ratio: 3:2

20x16” poster prints

DPI: 300* 
Resolution: 6000 x 4800 pixels*
Aspect ratio: 5:4

*For larger-sized prints, especially poster prints, you may need to reduce the number of pixels in the image to reduce the file size - as some photo printing services have a limit on file size. Whilst this could impact the quality of the print, we would recommend halving the DPI and resolution to 150 DPI and 3000 x 2400 pixels - keeping the aspect ratio the same.

30x20” poster prints

DPI: 300*
Resolution: 9000 x 6000 pixels* 
Aspect ratio: 3:2

*For larger-sized prints, especially poster prints, you may need to reduce the number of pixels in the image to reduce the file size - as some photo printing services have a limit on file size. Whilst this could impact the quality of the print, we would recommend halving the DPI and resolution to 150 DPI and 4500 x 3000 pixels - keeping the aspect ratio the same. 

There are many different ways you can resize an image for photo printing, depending on what device you are using or what applications you have available to you. 

Below we have listed the most common tools available to resize images:

How to resize an image in Windows Photos

If you have a Windows computer or laptop, you can resize images using Windows Photos:

1. Open your image in Windows Photos
2. Click "Edit & Create" and select "Resize" from the dropdown menu
3. Select "Custom Size"
4. In either the "Width" or the "Height" field, enter the new pixel count desired
5. Click "Apply" to resize
6. Click "Save a Copy" to save the new image if you are happy with the result

How to resize an image on a Mac

If you have an Apple Mac or Macbook, you can resize images in your photos app:

1. Open the image you want to resize in Preview
2. Click on the "Tools" menu and select "Adjust Size"
3. In either the "Width" or the "Height" field, enter the new pixel count desired
4. Make sure the "Scale Proportionally" box is ticked to keep the same aspect ratio
5. The preview will show you the new image dimensions
6. If you're happy, click "OK" to resize the image
7. Click “File" and choose "Save" to save the image

How to resize an image on Photoshop 

Photoshop can scare a lot of novices, but it is incredibly easy to use to resize images:

1. Open your image in Photoshop 
2. Click the image menu, then select “Image Size”
3. In either the "Width" or the "Height" field, enter the new pixel count desired
4. Keep the “Resolution” at 300 (or 150 if needed for poster prints)
5. Deselect “Resample”
6. Click “Ok” to resize the image
7. Click "File" and choose "Save" to save the image

Free desktop applications to resize images 

If you don’t have the tools above available to you, there are a wide range of free desktop applications that can also be used to resize images. These include:

• Adobe Express
• GIMP 
• Microsoft Paint 

Free online web applications to resize images 

You can also resize images on the web for free, on a wide range of online web applications including:

• Image Resizer
• PicResize
• Simple Image Resizer
• Resize Pixel

Resizing an image isn’t the only way to guarantee getting the perfect photo print. 

Use a professional printing service 

Many home printers aren’t designed to print high-quality photos, and as such, we recommend using a professional printing service for the best results. Our printers are designed to print the perfect pictures, and our helpful colleagues are always on hand to help if you have any problems. 

Print a test copy

We’d also recommend, regardless of if you’re using a home printer or professional printing service, to print a test copy before committing to a larger print run. This way, you won’t waste your money, or all your ink and photo paper stock, if the resolution isn’t quite right! 

Ready to bring your photos to life in vibrant colour and crystal clear clarity? Photo printing is just the tip of the iceberg of what you can do with all your special images. Explore our wide range of products, including photo books and personalised gifts, or check out our blog for more inspiration.