Add preview images

Sprite-compiler.md

@@ -5,8 +5,13 @@ This page documents OpenRCT2's built-in tool for importing and exporting of spri
 * **openrct2 sprite append `sprite file name` `image to add`** Adds the specified image to the end of the sprite file. Since OpenRCT2 has a limited colour palette, the image has to be converted. Currently, there are three modes of conversion, which can be specified by the option `-m`:
     * `-m 0`: default. This mode behaves the same as the importer did before. Any pixels not present in the colour scheme will be ignored.
     * `-m 1`: closest. This mode will change all pixels to the closest pixel in the palette. Already converted images will be unaffected.
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+    ![Converted using closest mode](http://i.imgur.com/tG3YFON.png)
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     * `-m 2`: dithering. This mode will use Floyd-Steinberg dithering to make the image look close to the original while converting to the colour palette. Already converted images will be unaffected.
 
+    ![Converted using dithering mode](http://i.imgur.com/EB0DmuI.png)
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 * **openrct2 sprite build `sprite file name` `image folder`** Creates a new sprite file and imports all files in the specified folder. This also accepts the modes as described in **append**. Every time the game is compiled, the images in \resources\g2\ will get added in this way automatically. It should be noted that if an image already uses the OpenRCT2 colour palette, none of the modes will change the output. Therefore, if the result of dithering is not to your liking, you can add your own custom image and still use dithering with this command for the other images. To learn how to do dithering yourself, see [dithering images](https://github.com/IntelOrca/OpenRCT2/wiki/Dithering-Images).
 
 * **openrct2 sprite export `sprite file name` `sprite index` `image to create`** Exports the sprite at the specified location in the sprite file to the image location.