Adjusting Headless Mac Resolutions
If you run a headless Mac server, one of the more common irritations is that VNC/Screen Sharing connections are often limited to a default resolution of 1024x768. Some enterprising companies make HDMI dummy plugs to simulate a connected displayed - thus setting the system's resolution to something more reasonable, like 1920x1080.
However, there are software-only approaches. My solution hinges on the functionality of an app called Display Menu. This app will allow you to pick a resolution regardless of an attached display or adapter. It's also has AppleScript support (as an in-app purchase). So I simply have a Keyboard Maestro Macro set to execute the following AppleScript at startup :
tell application "Display Menu" select resolution "1920x1080" end tell
Done.