Well, I was able to find a website offering a script , which can be inserted in GIMP, so you can draw arrows in any size !
Draw Arrow | GIMP Plugin registry
http://registry.gimp.org/node/20269
Screenshots below shows steps taken to insert script, and draw arrows in GIMP :
a) Download the "arrow.scm" script file from the link mentioned above.
b) Place the file in the scripts directory for GIMP , see screenshot above.
c) Place a path in the image file, and then go to Tools -> Arrow ... , to set the attributes for the arrow , and create the arrow (see screenshot).
Thank you "registry.gimp.org" ! .
There is one more way, use WINGDINGS 3, font , to create an arrow ( experiment on which letter creates the best arrow for you).
This screenshot shows an arrow created using letter 'a' , font Wingdings 3.
Note : All this screenshots were take in GIMP version 2.6.8 .
