The Skins I have available are 24bit Targa or.tga files. They are sized to be compatable with the Standard Graphics setting in the game's Options menu. These skins should be resized for use at other settings. Click here to compare the graphics settings to skin resolution and color depth.
Swapping skins is simple but you must work carefully. The basic technique is to replace the existing file with a new file that uses the original files name.
Did you realize that Boarder Zone installs a collection of Bulk clothing files in the Data/Characters folder? You can mix and match outifts by renaming and copy/pasting the new files into the Character folders.

Here is an Explorer view that illustrates the hieracrhy in your Boarder Zone directory.

The most important step is identifying and working in the appropriate folder. The Standard Graphics setting uses skins stored in the

Border Zone/Data/Characters/_character_name_/lores/24bit

directory. It is a good idea to rename the original files with a clever name so that they can be located easily when desired. Copy the new files into the folder and you are ready to play.