Bitmap images are a ‘map’ of pixels. They exist in a finite rectangle of some sort.
Vector graphics are a series of points plotted out with math. They are drawing instructions that get drawn in the browser.
A Bitmap/Raster image is not math. They are made up of a series of tiny boxes set with color or some alpha/opacity setting. Those little boxes all come together to form a picture, just like your television screen or a Chuck Close painting. Photographs can’t be drawn with an SVG.
.jpeg .gif and .png are all bitmap file types with their own pros and cons.