>>8038196>>8038792Vector images are made from (generally) mathematical curves and gradients. Like drawing with a graphing calculator. Benefits include smaller file sizes for certain kinds of images (e.g. glyphs, logos) and perfect sharpness at any zoom level. Websites use them a lot. There's not much of a point for images with arbitrary detail, like photos, which are more convenient to represent on a pixel grid.
Vectors are generally drawn from scratch using programs like Inkscape, not a converter.