Why are vector graphics so important, and what makes them unique?

Before I started learning web design, if someone brought up vectors, chances are I would think about physics, and something about direction and magnitude. Now, I’d think of a vector image or graphic.

You may not realize it, but on an everyday basis, you most likely come across several vector graphics. That company logo you saw on a billboard driving home? Chances are, it’s a vector graphic that was originally designed using a digital platform such as Adobe Illustrator. Think about the last website you scrolled through. If it was designed well, there were graphics and/or icons present. Some, if not all, were probably vector graphics.

So what exactly is a vector graphic?

In simple terms, vector graphics are created using mathematically defined elements known as “vector primitives”. These include points, lines, curves, and shapes. Since they are defined by a mathematical algorithm, these vector primitives are able to maintain a high image quality regardless of the graphic’s size.

Translation: if upscaled to a very large size, or if you zoom in very closely, a vector image will not become blurry or low-resolution.

You’re probably familiar with JPG images, like the ones you take with your camera or phone. Have you ever tried to expand a JPG photo to a much bigger size, only to wind up with a blurry mess? The same has probably happened if you attempted to resize a PNG image. These image types are known as “raster images”. Rather than being based on a mathematical definition, they are based on pixels — the same pixels that your computer screen display is comprised of.

So why do pixel-based images lose resolution if enlarged? Originally, every raster image is created at a certain resolution level, with a set grid containing a certain amount of pixels. The internal code of the raster image tells the computer exactly which color belongs in which pixel. If you try to enlarge the image, you are effectively “enlarging” the pixels themselves, which causes that blurry mess.

With a vector image, you never have to worry about pixels. Since the vector primitives that make up the graphic are based on mathematical algorithms, they can be infinitely enlarged or reduced to any size. You can see the difference between the enlarged raster and vector images below:

It is important to note that vector graphics can be converted into a raster format, but a raster image can NOT be transferred into a vector image. Because of this, it is always a good idea to start out with the vector format and convert to a raster image if needed.

I’ve mostly said negative things about raster images so far, but they do have their advantages. For one, JPG images are great for background images or landing pages, as long as the original photo is large and high-resolution. Raster images have the ability to display gradients (smooth transitions between different colors), while vectors do not. It is possible to incorporate “raster effects” to a vector if you want the appearance of a smooth color transition, but then your image is no longer a pure vector image.

Raster images also have the tendency to appear more life-like and realistic for the same reason listed above, whereas vector graphics and images appear less realistic. The image below gives us a side-by-side comparison.

In conclusion, both raster images and vector images have their specific uses and advantages. If you want a nice background image or some detailed pictures for your website’s gallery, stick with large, high-quality raster images. If you want to design a new logo or use some scalable icons on your website, it’s best to go with vector graphics.

To learn more about vector graphics and how they compare to traditional raster images, visit this page from vectorconversions.com.