There is no need to create any configuration by default. If you want some customizations as follows, you need to define <code>config/css_sprite.yml</code> file.

h3. ImageType

css_sprite uses RMagick to compose the images by default. It uses PaletteMatteType as default image_type, you can change it to any image_type which RMagick supports.

</code></pre>

<code>engine</code> defines css (default) or sass file to generate.

The customization above means if your image filename is button suffixed (e.g. post_button.png), the corresponding class .post_button has the additional style with (outline: 0; border: 0; and so on),

if your image filename is icon suffixed (e.g. twitter_icon.png), the correspondiing class .twitter_icon has the additional style with (text-indent: -9999px; cursor: pointer)

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