The term vectorization is not the precise term vector is in mathematics, but rather just the information to store in order to redraw the picture.

Sometimes this is a few points; sometimes it is a formula.

Most drawing packages use this type of storage.

In any case, it is enough information to reconstruct the figure, but not to edit it (since individual parts of the picture are not available to be changed.)

However, the object can often be resized by changing coefficients in the storage formulas.

Vectorization will reduce the size of a 300 dpi (dots per inch) picture to 1/200 of its original (uncompressed) size, but with some loss in quality.

Lotus DIF and PIC formats and Microsoft SYLK use vector formats.