Illustration by Tridib Das

A pixel, also known as a picture element (pix = picture, el = element), is the smallest adjustable point of a rasterized image. Each pixel can take on properties of over a million different colors—and when grouped together, they can portray an unlimited range of shapes and images. Essentially, pixels are the building blocks of the digital world, allowing designers to manipulate and set them to specific coordinates to bring an image to life.

In visual design, it is important to understand the overall structure of a pixel and how it can be manipulated to benefit the quality of your designs. To avoid common problems like pixelation and decreased web page loading speeds, let’s take a closer look at a single pixel and answer some important questions that will help guide you as you begin to work with pixels.

What is a pixel’s size?

When working with images, there are two key dimensions to consider as you determine the size of their pixels: The height and width of the image and the pixels per inch (PPI). The height and width measure the overall size of your image, whereas the PPI is the number of pixels that cover each 1×1-inch square of the image. A higher PPI means a greater pixel density, which will give you a higher resolution image. A lower PPI will do the opposite, making the image a lower resolution, which means it appears more pixelated.

How many pixels do I need?

One of the most important things to keep in mind when working with pixels is that the PPI within a given image directly correlates to its file size. If you are working with images to include on your website, larger image file sizes can cause significant delays in web page loading times. To avoid this, make sure your images are resized for appropriate web page viewing. For most standard websites, that equates to images that have 72 PPI. However, the number of pixels you need is dependent on the project you are working on.

For example, if you are a professional photographer, you will want to ensure that your photos have the most pixels possible to ensure your images can fit many different sized frames without causing pixelation. If you are worried about your images turning out overly pixelated, the next section will give you tips on how to avoid it.

How do I avoid pixelation when doing graphic design or photo editing?

One of the key things to look out for is whether your image has enough PPI. Fewer PPI and greater image sizes will lead to a more pixelated finished product. While an image might feature a high resolution and look crisp in your design software, accidentally selecting a lower PPI when exporting the image will result in pixelation.

Although a higher PPI will give you a higher resolution image, it is important to remember that it will also increase the image’s file size. It’s good practice to export your image at several PPI increments to see which is necessary for your particular use case. This ensures that an image meant for a web design won’t negatively impact your web page’s loading times.

What you need to know about pixels

Although pixels are small in nature, there are many important factors to consider when working with them to ensure they properly display on your design or artwork. Three of these factors are responsive web design, pixel density, and color information.

Responsive web design

When designing for a web page, you will have to take into account the variety of screen sizes and devices that will be used to view each page of the website. Responsive web design allows designers to adjust the web design grid and how their web page appears on devices like desktop monitors, tablets, and smartphones.

These different screen dimensions are referred to as breakpoints in web design. Because different breakpoints exist, designers must test how their images appear on a small screen versus a large screen. Without this test, an image that looks great on a smartphone may look severely pixelated when viewed on a laptop.

Pixel density

As we touched on earlier, pixel density is a key component to ensuring your image is as crisp as possible, giving it that high-resolution, polished look. However, a high pixel density combined with the overall size of the image itself will increase the image’s file size, which could negatively impact how quickly it loads on a web page. Rather than increasing your image’s PPI to the highest possible density, it’s best to try different increments to find the best image size and PPI for your particular use case.

Color information

Every pixel within an image stores specific color information. For images that will be displayed on a digital screen, pixels will use an RGB (red, green, and blue) color profile. Printed images, on the other hand, use a CMYK (cyan, magenta, yellow, and key/black) color profile and are measured in dots-per-inch (DPI) rather than PPI. In either case, each PPI or DPI will feature a unique color profile—and when placed next to other pixels in a group, they will form an image.

Start building with pixels

Pixels are the building blocks of the digital world. Although they are small, they can significantly impact how our designs are displayed on a variety of different screens and devices. That is why it is important that all designers, especially those participating in a designer-developer collaboration, take the time to understand the functionality of a pixel and how to leverage it to build even our most elaborate designs. When you’re working with pixels, be sure to check your image’s file size and pixelation, as well as making sure that you test out how your images look at multiple breakpoints.