Editing the Crosshair color?

[HKPhooE]

Hello, I found that the original crosshairs for jk2 would sometimes blend into the background of the map, which would throw off my aim. I downloaded the DS-Reticle, and found the neon green color very helpful. Unfortunatly, when its over an enemy, the neon green reticle turns completely black, which is counter-productive to me not wanting it to fade into the background. How would I go about changing the reticle color from the original black to say, a bright yellow?

 

I skimmed the custom reticle tutorial at massassi temple, and though I'm sure its very well done, the methods used are a little out of my league. Is there some bmp/jpg etc file I can open and just change the color from black to yellow in MS paint?

 

I unzipped the PK3 file that the DS-reticle came in, inside are a bunch of .tga files, do I need to open these? and how?

 

Anyways, will appreciate any help offered.