Necessary Software
First off , you'll need some sort of photo editing software that is capable of working with .dds files. The majority of editing software doesn't come WITH the capability of editing .dds files, and for those you will need plugins. Some that come to mind are Gimp, Paint.net and Photoshop, Gimp and Paint.net being freeware and Photoshop costing, well... a lot. Here are a few links to guide you to the proper software:
Gimp (the actual program): http://www.gimp.org/
Gimp (the .dds plugin): http://registry.gimp.org/node/70
Photoshop (the .dds plugin): https://developer.nv...adobe-photoshop
Paint.net (the actual program): http://www.getpaint.net/ (Direct .dds support, does not require plugins)
Obviously I can't link you to the actual program Photoshop, as that's what we call pirating, and that is bad. There may be a trial version however.
You will also need a program to extract the .dds files from the .pkg files that the game uses, as well as repackage your modified .dds files back into the .pkg files. The only ones that come to mind for me are 7zip and Winrar, 7zip being open source software and Winrar being a payed for program, but having a trial time period that you could use. Here's link for those as well:
7zip: http://www.7-zip.org/
Winrar: http://www.win-rar.c...nload.html?&L=0
For the rest of this guide everything you see will be done with Photoshop and Winrar, as that's what I use, though I'd imagine the other programs work pretty similar. Installing everything should be pretty simple so I'm not going to go through that process.
Locating the .dds Files
First off, after you've got your necessary software installed (if you didn't already have it), your going to need to locate the .dds files for the plane you want to skin. For this guide I'll be using the Bf 109 G, since it's the only plane I've FULLY skinned so far.
Navigate to where the .pkg files are located (mine are a little different since I didn't install in the default location, but you'll get the idea) and copy it to, for example, your desktop.

Next, change the file extension from .pkg to .zip, and select yes when it gives you the warning about changing file extensions. (A note on this: Alex mentioned that you do not have to change the file extension, but that you can simply extract the files using whatever extraction software your using.)


Now, using the extraction software we've got we simply extract the files. I always use the "extract to (insert file destination here)" method, as I find it's the easiest, and I can always move the folder/files around afterwards.

Now we've got all those folders with all those .dds files. (Mind you I've got some extra .psd files from previously working on skins.)

Editing the .dds Files
Let's go ahead and open the GR11_BF109G_hangar file (default skin file). You can do that by opening it through your photo editing software or, since we installed the .dds plugins, simply double click the file. (You may have to right click the file, select properties, and make whatever program your using the default for this to work, and if you do if makes life much easier.)

Once the program starts up and the file opens you'll get a little box like this. Make sure you open the file at the default sizes.

Now you've got your skin open in your photo editing software and your free do play with it as much as you want, just make sure you don't rotate it, or it will look all sorts of weird in game because nothing will match up right. Then when your done playing around with it, simply save it over the currently existing .dds file.


When you go to save it you'll get yet another dialogue box like this. Make sure you've got everything set like I do in this picture. (It's all default so I'd imagine Gimp users can just leave everything defaulted.)

Repackaging the .dds Files
Now we go ahead and open our extracting/packaging software, locate, and open the games .pkg archive.




When your locating the .pkg archives within your extracting/packaging software you'll have to make sure it's looking for all file types, as the .pkg files may not show up otherwise. Once you do that you'll be able to see the .pkg file.


Now, still within the extraction/packaging software, we navigate to where the .dds file is located.




Now you'll click and drag the .dds file you modified pretty much anywhere in the folder you have open with your extraction/packaging software, with the exception of into one of those top three folders.

Now you'll get one last dialogue box. Make sure you have everything set like I do. (Aka: The default way.)

That's it, now your ready to go fly your pretty new plane!
Final Notes (Notes with dates have been added at a later time, just putting the dates there to make new ones easier to find.)
Please note that you should not have WoWP open while doing all this. Aside from the demand on your computer, you won't be able to repackage your .dds files if it's open. It should also be noted that you need to back up your original .pkg files in case you mess anything up.
I have heard that some planes are not skinnable. I however have not yet run into this problem, though I have not skinned every plane in the game, so you may come across one that you can't. I have also run into problems with blanking out the country insignia, kill markers, unit numbers, and the other common files. The last time I tried messing with them I broke something or other and had to resort to reinstalling to fix the issue. (My fault for not backing anything up.)
4/15/2013
It does not SEEM that changing the image size of the .dds file affects the skin, at least not increasing it, as long as you go in multiples rather than decimals. For example, I was able to 4x the size of the P-51A skin with no problem, albiet a huge file size. Another note on that as well, keep in mind if you do increase the size of the image, the greatly increases the size of the file, therefore decreasing game performance. Testing it on the 51A, when I 4x'ed the image, the file size shot up to roughly 30mb, though it does look better. Just something to keep in mind.
I take no responsibility for broken games. Modding any game is a risk, but if you do it properly everything should be fine.
Have any questions? Feel free to ask. Also, if there is any way I can improve this guide, please do let me know, as this is an ongoing project of mine.
Lastly, a big thanks goes out to DrSinister for helping me figure out how to get skins to work in WoWP.
Edited by SdKfz_181, 15 April 2013 - 05:15 AM.