Image resolution: What does it mean?

For many clients working with graphic designers, the issue of image resolution has been brought up. As designers we’re always requesting high-resolution images from clients for print projects. Many clients, however, might not know what these are or why they are so important to us. So we’ve put together a guide to help explain.

So what is resolution?

The Dictionary definition of resolution is: the degree of detail visible in a photographic or television image.

In basic terms, the resolution quality of an image depends on how many dpi (dots per inch) or pixels make up the image. Images are usually measured in pixel width and height. These measurements determine whether images are high or low-resolution. Web images are always set to 72dpi whereas print images need to be set to 300dpi to be sharp when printed. For this reason, images taken from the Internet will never look sharp in print. They will always appear fuzzy or blocky so we strongly recommend not using web images in print.

The example above shows the difference between high and low-resolution images. The image on the left is high-resolution set at 300dpi. The image is sharp and looks good. The image on the right is low-resolution set at 72dpi. Although the two images are the same size, the right-hand image is blurred and unsuitable for print.

How can I tell if I am supplying high-resolution images?

If you are a PC user, right-click on the actual photo file. A list of options will pop up with “Properties” at the bottom. Left-click on “Properties.” A window will open with two tabs at the top, “General” and “Summary.” Left-click the “Summary” tab. Midway down that tab you’ll see “Advanced.” Left-click on “Advanced.” You can now see the Width and Height of your photo in pixels, as well as the dpi resolution.

If you are a mac user, select the image in the Finder and right-click. “Get info” will appear in the list. Click this to open the info window. Click the arrow next to “More Info” for the image dimensions in pixels. The Finder does not display the dpi resolution.

The file size of the image can also be a good indicator of quality. Images under 1mb (megabyte) will generally be unsuitable for printing.

Below is a chart to help you determine what size your 300dpi high-resolution supplied images should be:

Paper "A size" Size in CM Size in Pixels

A6 10.5x14.8 1240x1754

A5 14.8x21 1754x2480

A4 21x29.7 2480x3508

A3 29.7x42 3508x4961

We hope that this has explained the importance of high-resolution images and we have made it easier for you to check the images you send us to ensure the best quality print results. Download our Guide to Image Resolution to keep and print for reference.