//Remember default preferences
startRulerUnits = app.preferences.rulerUnits

//Set Photoshop preferences
app.preferences.rulerUnits =Units.PIXELS

reSampleMethod = ResampleMethod.NONE

var docRef = app.activeDocument
var docHeight = docRef.height
var docWidth = docRef.width

if (docHeight > docWidth)
{
docRef.resizeImage(533,800,72)
}
else
{
docRef.resizeImage(800,533,72)
 }

//Reset preferences
app.preferences.rulerUnits = startRulerUnits