loFSO = Createobject("Scripting.FileSystemObject")
filepath = 'U:\questpdm\picture\whatever.jpg'
loFile = loFSO.Getfile(filePath)

IF loFile.Size <= 500000
   MESSAGEBOX("File Size is OK")
ELSE
   MESSAGEBOX("File Size is not OK - File Size="+TRANSFORM(loFile.Size))
ENDIF