In IH4 header_php.php files i found out a section which was commented out and a note that :
//End Image Handler changes 2 of 2 (this entire section is commented out for Image Handler 3)

though i have never installed IH3 (or IH2 or any other version of IH).

Does this section need to be there and NOT commented out ?

Or is there any other problem with my installation or procedure ?

other core files seem untouched to me comparing with the backup, barring changes made by IH4 to the core files

Thanks