Nowadays, when we talk about graphic design, there are two major software: Illustrator and Photoshop. Adobe Illustrator is an advanced vector-based software which is used to edit words and texts. Even though its function is similar to Photoshop, the graphical construction is totally different from Photoshop. Illustrator uses mathematical constructs to create vector graphics while Photoshop uses pixel-based format. For example, in Illustrator, a square can be four dots connected by a computer algorithm, instead of just 4 lines of pixels. Therefore, Illustrator is more flexible on printing because the image quality will not change with scaling. For Photoshop, even though the quality of image will be lost quickly if we change the scale, it is more convenient and useful on fixed-sized photo editing and designs. The image in Photoshop contains lots of unique filters, special effects and tools, so you can change the image precisely. Since the Photoshop file will contain multiple layers, the size of the file will typically be much larger than the Illustrator file, while Illustrator cannot edit images as precisely as Photoshop. So each software has its pros and cons, we just need to pick the proper one based on our need.