A vector is an infinitly scalable image created using paths and shapes rathar than pixels. They are commonly made in Photoshop or illustrator through the use of the pen tool. Vectors can also be made in Inkscape, which is a free to use open source vectoring program, along with many others. Files made using Inkscape, which are saved in the SVG format can also be opened by web browsers. More information can be found here:
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