I'm making menus for my SVCD's. While playing around with VCDeasy's mpeg still options I found 4 settings that I have no idea what they do.

Resize Filter:
Nearest
Spline
Linear
Linear2

What are these?

Also I wanted to ask, how come Vcdeasy stretches my 704x480 menu images when converting to mpeg stills unless I check the option "hacked" under where it says SVCD?