What is Illustrator used for?
Simply put, Illustrator is a computer program created for drawing or illustration. It helps the digital artist have direct control over the image created from the shapes to colour application as well as customized typography. This program is often used for poster design, business cards, labels, t-shirt designs, logos and any other type of graphic that is NOT based on a photo.
Vector Files: A Refresher...
Illustrator can read digital image files such as JPEG and PNG, but creates files that are VECTOR. This means, that artwork created in Illustrator can be enlarged indefinitely because it is NOT based on pixels, but rather mathematical calculations of lines and angles. This prevents pixelation or blurriness while retaining a relatively small file size, but somewhat places limits on the complexity of the image in terms of details and colours. For example, with a vector file the same file can be used to create a business card as well as a billboard with equal quality or resolution.