The difference between vector and pixel

In the world of graphics, there are two main formats:

 

Vector (usable files lik.eps, .ai and .pdf)
Vector graphics is composed of mathematical points connected by lines and bows. When this type of graphic is used, motives can be scaled up and down with out any loss of quality.

Rasterized/Pixel (un-usable files like .jpg, .gif., .png and bitmap)
Rasterized pictures (or bitmap pictures) are composed of a pattern of pixels (small squares) that have a specific color value. Since the motive is composed of a set number of pixels, an upscale will only enlarge these small squares. The result will be a grainy picture.
Should You only possess the file in a rastorized format, we are able to create something from it, but it demands that we ink/vecorize the file.
To achieve the best result from inking, the picture we use needs to be of a quality where the text can be read and details in the motive seen. So the larger the image is, the better will the quality be.

Note: renaming a .jpg file to a .pdf file does not vectorize it.