Your skin needs to go in its own folder in the aces high\skins folder. This should be named in the following way: If your skin is a p51d the folder would be called "p51d_1". A second p51d skin would be put in a folder called p51d_2 and so on.
Inside the folder your skin file would be called "p51d.bmp". This needs to saved as a 256 colour bmp.
Also you need a description file called in this case "p51d.txt". This is a simple text file that can be created with notepad. The text inside it shows up in the game so you can tell which skin is which. It should say something like "123FS/45FG by Bosco123".
When you open the game, you go into the hangar and your skin should show up in the dropdown box for that aircraft.
