Raster vs Vector Images: The Key Differences Explained

Side-by-side comparison of a dog photo in raster format and vector format

estimated reading time: 5 minutes

Raster vs Vector: Understanding These Two Popular Image Formats

A Raster Image of a dog on the left next to a Vector Image of a dog on the right — A Raster image (left) is able to exhibit fine details and gradual variations in tone. As such, the Raster format is excellent for depicting realism. Conversely, the Vector image on the right can only display areas of solid color, limiting its level of detail and creating more abrupt changes in tone. Hence, photographs in a Vector format will have a less realistic "paint by numbers" appearance.

When it comes to digital graphics, there are two primary types of images: Raster and Vector.

Each has unique strengths and limitations, so it is important to understand how these two image formats differ. Selecting the right one for your specific project can mean the difference between a crisp, professional-looking image and one that appears blurry or distorted.

In this article, we'll explain what Raster and Vector images are, how they differ, and the best uses for each.

What Are Raster Images?

Raster Images, sometimes referred to as Bitmaps, are made up of thousands upon thousands of tiny individual squares called pixels.

Each pixel displays a specific color value. Arranged in a grid-like formation, pixels are the fundamental building blocks of a Raster image.

When viewed collectively at normal size, the pixels form a complete image with smooth color transitions. However, if you were to increase the dimensions of a Raster image beyond its original size, the individual square-shaped pixels become more visible, distorting the image (see example image).

A small photo of a woman's face next to an enlarged version of the same photo — *Raster images can appear blurry and jagged when enlarged beyond their original size*

What are the most common Raster File Formats?

JPEG (.jpg) - Joint Photographic Experts Group
PNG (.png) - Portable Network Graphics
TIFF (.tif) - Tagged Image File Format
GIF (.gif) - Graphics Interchange Format
BMP (.bmp) - Bitmap

What are the Advantages of Raster Images?

Intricate Detail and Realism - a Raster image can display fine details, complex color variations, and subtle gradients. This makes it the ideal file format for photographs and realistic artwork.

Universally Compatible - common Raster file formats (.jpg, .png, .tif, .gif, .bmp) have widespread compatibility with most operating systems, design software, and devices.

Precision Image Retouching - because Raster images are pixel-based, this allows for precise image adjustments at the individual pixel level. For examples, pixels can be added or removed, or have various attributes altered such as color and brightness.

What are the Limitations of Raster Images?

Quality Decreases when Enlarged - a Raster image is resolution-dependent, so enlarging beyond its original size merely stretches the existing pixels, resulting in less detail not more. Also, as the pixels gain size, their square edges become more visible. This leads to a jagged appearance and reduces the sharpness of the image.

Larger File Sizes - high-resolution Raster images require a lot of storage space, especially as the dimensions and pixel counts increase.

Unsuitable for Certain Graphics - because Raster files are composed of a fixed grid of pixels, they lack the flexibility needed for logos, icons, and illustrations that require sharp lines and infinite scalability.

A 2x2 grid displaying four examples of company logos — *The Vector file format is perfectly suited for Logos and Icons*

What Are Vector Images?

Vector Images are created in a completely different way from Raster images. Instead of being pixel-based, Vector images use mathematical formulas to define shapes - using points, lines, and curves - into which various fill colors are placed. In other words, a Vector file does not store a finite grid of colored pixels, it stores instructions for how the image should be drawn.

Because Vector images are defined by mathematical formulas instead of a fixed grid, they can be scaled infinitely - up or down - without losing image quality. The formulas for the shapes and color fills are simply recalculated at the new size. This means the same Vector logo will look crisp and sharp whether printed on a small item, like a business card or envelope, or on a large item like a banner or tradeshow backdrop.

What are the most common Vector File formats?

AI (.ai) - Adobe Illustrator
EPS (.eps) - Encapsulated PostScript
SVG (.svg) - Scalable Vector Graphics

What are the Advantages of Vector Images?

A small illustration of a woman's face next to an enlarged version of the same illustration — *Vector images retain their sharpness when enlarged*

Infinite Scalability - because Vector graphics are based on mathematical formulas, they are resolution-independent. As such, they can be easily resized up or down without losing clarity.

Smaller File Sizes - compared to high-resolution Raster images, Vector files are usually much smaller in size. This is because they only store instructions for generating shapes and colors rather than data for thousands or millions of pixels.

Easier to Edit Individual Elements - the design components within a Vector image, such as shapes, lines, text, and colors can be adjusted independently without affecting the entire image. Hence, Vectors are very flexible for design changes.

What are the Limitations of Vector Images?

Not Suited for Complex Images - Vector graphics are limited in their ability to represent detailed photographs or images with continuous color gradients, shadows, or textures.

Limited Realism - Vectors are excellent for creating clean, flat designs, but they aren't able to replicate the natural look of real-world objects the way Raster images can.

Potential for Software Incompatibility - some programs or platforms may not fully support Vector file formats, potentially requiring conversion that could lead to a loss of quality or features.

Raster vs Vector: Key Differences at a Glance...

A table comparing the traits of Raster images to Vector images

Final Thoughts

Understanding the difference between Raster and Vector graphics is essential for anyone working with digital images. Here's a quick review…

Raster Images are the perfect choice for photographs or complex visuals. If a project involves detailed shading, textures, or a wide range of colors, Raster is the better option.

Vector Images are the perfect choice for logos, icons, typography, and illustrations. If a project requires clean design and unlimited scalability, Vector is the better option.

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