just drag the .iwi in your /modname/images folder.
Sorry but you are not allowed to view spoiler contents.
if u wish to put the sight on other snipers/guns, just open up the gun file and look for: "adsOverlayShader" and replace the current one with the new one.
\adsOverlayShader\scope_overlay_american\ <-- old from the springfield
\adsOverlayShader\scope_overlay_mp\ <-- new one