Which one of the following is not a raster image format ?

Digital images are primarily classified into two types: Raster and Vector.

• Raster (Bitmap) Graphics: These are composed of a fixed grid of pixels. When resized, they often lose quality or become "pixelated." Common raster formats include JPEG (Joint Photographic Experts Group), GIF (Graphics Interchange Format), and PNG (Portable Network Graphics).
• Vector Graphics: These are based on mathematical paths (points, lines, and curves) rather than pixels. SVG (Scalable Vector Graphics) is a prominent vector format. Because it is defined by mathematical equations, an SVG image can be scaled to any size without losing resolution or clarity.

Since JPEG, GIF, and PNG are all pixel-based raster formats, and SVG is a path-based vector format, SVG is the correct answer as it is not a raster image format.