In a simple sense, Vector graphics are not pixelated (not based on pixel) on the other hand Raster graphics is based on pixels. Vector graphics are the form of digital art that is rendered using a mathematical formula, while raster uses pixels or tiny dots that works with colors to form or create an image.
So what is Pixel??? The pixel (“picture element”) is the basic unit of programmable color on a computer display or image. The size of a pixel varies according to the resolutions for the screen. Basically, pixel used RGB colors and different forms of their blend for the specific indication. The bitmap is the file that marks the color for each pixel.
Vector graphics deals with the line segments that are mathematically calculated. The colors of vector arts are stored inside those line segments. So the colors adjust in accordance to the outlines(path/lines) regardless of pixels, for example, if a cube is drawn with its dimensions 4*4 and suddenly if we enlarge the cube to 6*6 the colors will automatically fill up the area bounded by the bigger cube.
Raster graphics entirely depends on pixels. Here re-sampling the image will affect the quality of the image, for example: if we enlarge the 2*2-dimension image to 4*4 we may not find the sharp color difference as we may find some intermixing of colors in some spots. The file size of vector images is comparatively smaller than that of raster images. Vector arts use EPS, SVG, Al, and Raster uses BMP, GIF, JPG, PNG, TIFF as their file formats. Adobe Illustrator can be the best example of software for vector arts and Adobe Photoshop can be the most relevant for Raster arts. Display devices like monitors etc and printers are raster devices that use pixels to present images hence every vector file is needed to convert into a raster one for many purposes.
Thank you Suwarna Pyakurel, +2-SOS HGS Sanothimi