Hello,
There is no way to find out the size of a file be it a image or anything via pure javascript and client side only. Modern browser won't allow access to the physical file residing on client's PC, In fact they won't even allow your script to know the real path. However you may be able to do this using little Ajax and JQuery File Upload plugin such as
BlueImp[
^] or
Uploadify[
^].
Regards,