I know Photoshop, what is the difference with Illustrator?
The biggest difference is that Photoshop works with pixels (raster files, bitmap files) and that Illustrator mainly works with vectors. These vectors are very handy to create artwork that is resolution independant. This type of artwork will look great when projected, too, and one can zoom in on them without quality loss. If you upscale objects in Photoshop, or indeed zoom in, you will lose quality, even if it’s visual quality. Illustrator allows you to work efficiently and easily when you create a design. Changing colours of objects, separating colours, moving elements around: there is no better application for free artwork than Adobe Illustrator. It is even used to design websites. You can not build a website in Illustrator of course, but design-wise nothing beats it. Photoshop is used to edit photos and scans. You can not edit photos in Illustrator.
