What's the Difference Between Raster and Vector?
Raster (or bitmap) images are generally what you think about when thinking of images. These are the types of images that are produced when scanning or photographing an object. Raster images are made using pixels, or tiny dots containing unique color and tonal information that come together to create the image.
Since raster images are pixel based, the image quality depends on the resolution. Resolution means the number of pixels that make up an image as well as how many of those pixels are displayed per inch. As you may have guessed, the more pixels in the image and the more pixels per inch, the higher quality the image will be.
High quality raster images tend to be large file sizes because there are so many separate pieces of information (pixels) for the computer to process. Large file sizes can sometimes stall programs.
Enlarging a raster image can also reduce the image quality. This is because we are stretching the pixels over a larger area, thus making them look less sharp. If we resize an image using more advanced software, the computer must still guess at the missing pixels to fill the new space. This is why enlarged raster images can become blurry or pixelated.
You can filter image selections in Google by doing and image search, selecting Search Tools, and choosing the Size you prefer from the drop down menu.
Common Raster Image Types: JPG, TIFF, GIF, PNG, BMP
Instead of trying to keep track of the millions of tiny pixels in a raster image, vector images, or line art, keep track of points and the equations for the lines that connect them. Generally speaking, vector images are made up of paths or line art that can scale to any size because they are made mathematically.
One of the greatest things about vector images is that you can re-size them infinitely larger or smaller, and they will still print out just as clearly, with no increase (or decrease) in file size. Because the computer does not need to process hundreds or thousands of separate pixels, the file size of vector images is quite small compared to raster images. This allows your computer to process these files much more quickly.
So, what types of graphics would typically be vector? Well, almost all computer font files are based on vector images of the letters - that's why it's possible to scale them WAY up or WAY down and still have the letters be clear. All Microsoft Office clipart (discontinued in Office 2013, but still searchable in Bing) uses vector art and most charts, shapes and graphs produced by Office are vector-based. Vector illustrations are great for logos, illustrations/artwork, animations, and text.
Common Vector File Types: EPS, SVG