Pixels versus shapes
A raster image is a grid. Every pixel carries a color, and the whole picture exists at one fixed width and height. Photos are always raster, because a camera sensor records light as pixels. JPG, PNG, and WebP are raster formats.
A vector image describes shapes: points, lines, curves, and fills calculated from coordinates. Because the drawing is instructions rather than pixels, the software can redraw it at any size. SVG is the common web format, while AI and EPS are common in design work.
Scaling and file size
Scale a raster image past its native size and it softens, then blocks appear, because no extra detail exists. Scale a vector and the software simply recalculates the shapes, so a logo stays sharp on a business card and on a shop window.
File size follows the same logic. A detailed photo is heavy because every pixel is stored, while a simple vector logo is often tiny even at large sizes because a few hundred instructions describe it. Complex vectors with gradients and embedded pictures can grow, but clean artwork stays small.
Where each one fits
Use raster for photographs, screenshots, and anything with continuous tones. Use vector for logos, icons, diagrams, and type that must be resized or recolored later. Print work mixes both: a page can hold vector text and a raster photo at the same time.
Filekind converts raster formats, moving images between JPG, PNG, and static WebP. It does not convert SVG or other vector files, and it does not turn a raster logo into a vector. Export artwork as a raster image when you need it in a JPG, PNG, or WebP workflow.