This article describes how to change which program is used to automatically open certain types of files. For example, your PNG files automatically open in Preview, but you’d like for PNG files to automatically open in Adobe Illustrator; you can change that setting by following these instructions:
1. Open Finder. Choose any file that is the type you’d like to change (in this example it’s .png).
2. Right-click the file and choose Get info.
3. From the menu that pops up, scroll down to Open with: and choose the program you’d like to use.
4. Click Change All… and then click Continue.
The program you selected will now be used to automatically open all files of this type.