If developing on a PC with a High DPI monitor (>1920) then you will get graphics changing sizes between design time and run time.
This is fixed by adding a key into the Windows registry:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\devenv.exe]
"dpiAwareness"=dword:00000000
You can read more about this here:
https://code4ward.net/2016/11/29/visual-studio-winforms-designer-on-highdpi/