An EPS file is a file format for vector illustrations that is commonly used in print and digital media. EPS stands for Encapsulated PostScript, and it was created by Adobe in the late 1980s to serve the needs of designers and printers. EPS files are vector files that use a mathematical equation to store the information of each pixel in an image individually, allowing the image to be scaled up or down without losing its dimensions and resolution.

EPS files are essentially PostScript programs saved as a single file that includes a low-resolution preview "encapsulated" within it, allowing some programs to display a preview on the screen. EPS files are more-or-less self-contained, reasonably predictable, PostScript documents that describe an image or drawing and can be placed within another PostScript document. EPS files frequently include a preview picture of the content for on-screen display, which allows a simple preview of the final output in any application that can draw a bitmap.

EPS files are widely used by publishers because of their compatibility across different operating systems. They are ideal for scaling images, and the image data they retain ensures that the resolution remains high, even when stretched or blown up to larger proportions. EPS image data benefits from a lossless form of compression, which ensures that picture quality remains high, even when the file gets downsized.

EPS files can be opened and edited with Adobe Illustrator, but there are also many free software options available to open and convert EPS files. EPS files are best used for high-quality document printing and marketing materials, including advertising campaigns, billboards, band illustrations, t-shirt designs, brand collateral like logos and signage, and event promotions.