Ok not sure if im posting this in the right place but Here it is
Credit to CodeBrain for this one:
First, open up your rom with NDS Top System. Then load your Rom.
Then, go to the browse section, and open the poketool folder. (Look at image Tut-01 in attached.)
Go into the pokegra folder, and right click on pl_pokegra. Click extract and save it somewhere. (Look at images Tut-02 and Tut-03 in Attached.)
Open pl_pokegra in Poke DS/Pic Platinum. Head down to number 1495, and click the SavePng option. Save it in the a folder with any name. Do this with 1497, and 1499 as well (Save them in same folder!) (Look at images Tut-04, Tut-05 and Tut-06 in attached.)
Open them all in Adobe Photoshop. Look at the FRONT sprite. Click on Image, then Mode, and finally on Color Table. (Look at images Tut-07, and Tut-08 in attached.)
Edit the colors as you wish, but only from the COLOR TABLE. In this case, I recolored Lugia into Shadow Lugia. Here is his sprite:
While still in the Color Table menu, click the Save button, and name it something. Look at the back sprite. Click Image, Mode, and finally Color Table. (Look at images Tut-09 and Tut-10 in attached)
Click load, and find your previously saved table. (Last step) Your image SHOULD look the same as this:
If it only looks slightly different, then it shouldnt be a big deal. When I say small, I mean like the eye color is different. Just replace it with the real color thats in the COLOR TABLE ONLY. If it really looks different (aka the purple is orange) then your not using the same palette.
Save both images, doesnt matter if it's interlaced or not (I dont think it does...). Open Pokemon DS/Pic Platinum (In case you closed it) and go to #1495. Replace this image and the next one with the Shadow Lugia back sprite. Replace #'s 1497, 1498, 1499, and 1500 with Shadow Lugia's Front sprite. (Look at images Tut-11, and Tut-12, in attached.)
If done correctly, no palette errors should occur. If there is (Such as a corrupted image or colors arent right, etc.) See the FAQ. Open NDS Top System, go to the Poketool folder, then the pokegra folder. Right click on pl_pokegra.narc, and click import. Find your edited pl_pokegra.narc, and import it in. Load up your game and see if it worked!
I made a shadow lugia sprite
Also thanks to SCV for making PokePic Platinum