[agracier]

A good working knowledge of how graphics editors work is really a necessity. If you can work reasonably proficiently in GIMP, Adobe Photoshop or Paint Shop Pro (or others) then you should be able to add something simple like a sharksmouth to an existing skin..

But even so, you can't just always add something to an existing single layered bmp file, you really need to work in layers and preferably with an existing template.

You can download many aircraft templates at Flying Legends or Mission4Today or Simmers Paintshop.

Sometimes watching an introductory tutorial helps you better grasp how to work.

Here is a link to a few skinning tutorials.

http://www.sendspace.com/file/ak6afm