# File Extensions

Let’s talk about file extensions and what they all mean.

.jpg - this is the most common for saving photos.

.png - this allows you to keep a transparent background and is common for logos.

.psd - this is a photoshop file.

.pdf - this should be used if you’re exporting a document or presentation.

.ai - this is an illustrator file.

.svg - this is a vector file.

.eps - this is also a vector file.

So what does all this mean? The biggest difference here is vector vs. raster. Raster graphics are composed of pixels, while vector graphics are composed of paths.

A raster graphic, such as a png or jpg, is an array of pixels of various colors, which together form an image. If you zoom in to a raster image you may start to see a lot of little tiny squares.

Vector graphics are mathematical calculations from one point to another that form lines and shapes. If you zoom into a vector graphic it will always look the same. When you enlarge a vector graphic, the math formulas stay the same, rendering the same visual graphic no matter the size. Vector graphics can be scaled to any size without losing quality.

Do you remember algebra back in high school? X is the horizontal axis and Y is the vertical axis, and when you write an equation it creates a line or curve. For example, the quadratic function makes that upside down hill looking curve? Those are all vectors and that’s a simple way of explain how software like illustrator works!! (Fun fact: I started college majoring in calculus and then I realized I did not want to teach highschoolers and switched to graphic design!!)