Adobe Illustrator is arguably the most popular and most powerful vector graphics software. If you ever work with a designer, it is very likely that you will have to deal with .ai files. Even if your final files must be in a different format (PNG, JPEG or something else), it would be nice to have vector sources in addition to them – it will make your life much easier if you need to change something and cannot hire the same designer again.
But how do you open an .ai file, if you don’t have Adobe Illustrator – which is a complex and expensive piece of software hardly used by anyone except professional designers? In most cases it’s really easy — you need only free Adobe Reader software, which is already installed on most computers. Right-click the .ai file you need to view, point to Open With… and then click Choose Program and choose Adobe Reader from the list. Or you may simply change the .ai extension to .pdf and open the file by double-clicking it.