From the Help section of this very website:
"The Upload Noseart button can be used by the squad CO to upload a 64x64 noseart graphic. Graphics are not displayed in the game nor on the web page until they have been reviewed by the HTC staff. The transparency color to use in order to make your noseart blend into the plane is {176, 176, 176}. To upload a graphic, make sure your 64x64 bitmap file is named with your Game ID and is in your ../HTC/Aces High II/squads/ directory. Next, click the Upload Noseart button. Once the noseart is approved, your squad members may force the new image to download by deleting the existing noseart in their ../HTC/Aces High II/squads directory."
