"cobra3_redux.png" file that I modified and I saved this new version into the AddOns folder
This is the texture of the old model used until 1.77. Now you should modify the oolite_cobra3_diffuse.png and place into an AddOns/my.oxp/Textures folder if you do not want to replace it in the original place.
as a follow up: the new default textures come as RGBA. I don't know much about PS but if you want to edit them you have to decompose them to seperate R, G, B, Alpha channels with it as well. Save the Alpha for later. Recompose as RGB texture. Now, edit your texture (e.g. work with layers, paste your decals etc). If you are finished, flatten the texture in case you used layers. Add a black layer mask, copy your former Alpha channel into it, export the finished texture as PNG. Done.
I put the already decomposed cobra3 base diffuse texture and the saved alpha lightmap online here
/e: I thought there might be more people interested in customizing just their player ship (instead of all cobra3s), so I uploaded an experimental oxp here
, that replaces the player cobra3. You just have to edit textures to your liking and follow the Howto in the readme folder to export the finished texture.
/e2: updated the oxp with a layered example xfc:
The example texture features a "! I break for Anacondas !" bumper sticker layer, the pseudo decal layer, two layers for the two colours and a greyscale base diffuse texture.
hope it helps,