Enlarged screen

[KimT]

Hi - My IMac screen keeps enlarging. I'm pretty sure I'm doing something with the mouse, but can't for the life of me think what it is or how to get it back to normal size again! Any tips please

 

[Terry Corder]

My Mac Mini does that as well, time for a re-start.

 

[Cory Cooper]

Hello and welcome.

-Which model iMac?
-Which version of OS X/macOS?

Sounds like you have an Apple Magic Mouse and Smart Zoom enabled. Smart Zoom will zoom a browser window when you double-tap with one finger. Or, is the entire screen zooming?

C