PreviewPack
This section in a map file contains the picture that is to be used as the map preview. The dimensions of this image are given in the Preview section. The image itself is stored as a base64-encoded string of LZO compressed data that, when decompressed, contains the image in BGR format. The scanline of each row of pixels is precisely 3 times the width, i.e. no additional padding is used. For official maps, the dimensions of the preview image are 1.975 times the width of the LocalSize and 1.0 times the size of the height of this LocalSize.
There is little need to edit this manually, as XCC Mixer can create this section from any desired picture, which can then be pasted into a map file. This is used in the newest version of the Assault Mappacks to display an informational picture to users which are playing an Assault-compatible mod without downloading the mappacks themselves. (See the Assault Mappacks page for more info.) The map editor Final Alert is also capable of generating previews based on the tiles of the map. Higher quality previews can be obtained using a resized picture of the full map. The CNCMaps rendering tool contains an option to directly inject a high-quality preview into the map.
