C# Sprite Generator / Maker (zero config) - generates a sprite-sheet with css classes outputted as a string

SpriteInfo.cs

internal class SpriteInfo
{
    public string Name { get; private set; }
    public int X { get; private set; }
    public int Y { get; private set; }
    public int W { get; private set; }
    public int H { get; private set; }

    public SpriteInfo(string name, int x, int y, int w, int h)
    {
        Name = name;
        X = x;
        Y = y;
        W = w;
        H = h;
    }
}

SpriteMaker.cs

/// <summary>
/// Add images in a target dir and output as a base64 png sprite sheet referenced in a generated style sheet with css classes
/// Reference - http://codeinreview.com/126/generating-a-css-sprite-image-file/
/// TODO: provide various sprite sorting alg options e.g tilings, vertical. Only hoz at the moment.
/// TODO: Provide alt return type of stream. Only string at the moment
/// TODO: Convert to github repo?
/// </summary>
public static class SpriteMaker
{
    public static string Execute(string path)
    {
        var info = new DirectoryInfo(path);
        var dictionary = new Dictionary<FileInfo, Image>();
        var padding = 10;
        int maxWidth, maxHeight;
        maxWidth = maxHeight = 0;

        foreach (var file in info.GetFiles())
        {
            var img = Image.FromFile(file.FullName);

            maxWidth += (img.Width + padding);
            maxHeight = Math.Max(img.Height, maxHeight);
            img.Tag = Path.GetFileNameWithoutExtension(file.FullName);

            dictionary.Add(file, img);
        }

        var generated = dictionary.GenerateSprite(maxWidth, maxHeight, padding);

        using (Bitmap sprite = generated.Key)
        using (var memoryStream = new MemoryStream())
        {
            sprite.Save(memoryStream, ImageFormat.Png);
            byte[] bytes = memoryStream.GetBuffer();
            return GenerateStyleSheet(Convert.ToBase64String(bytes, Base64FormattingOptions.None), generated);
        }
    }

    /// <summary>
    /// Iterate over each sprite and add to sprite sheet
    /// </summary>
    /// <param name="dictionary"></param>
    /// <param name="maxWidth"></param>
    /// <param name="maxHeight"></param>
    /// <param name="padding"></param>
    /// <returns></returns>
    internal static KeyValuePair<Bitmap, List<SpriteInfo>> GenerateSprite(this Dictionary<FileInfo, Image> dictionary, int maxWidth, int maxHeight, int padding)
    {
        var sprite = new Bitmap(maxWidth, maxHeight);
        var spriteProps = new List<SpriteInfo>();

        using (Graphics graphics = Graphics.FromImage(sprite))
        {
            int xCoord = 0;

            foreach (var kvp in dictionary)
            {
                using (Image img = kvp.Value)
                {
                    graphics.DrawImage(img, xCoord, 0, img.Width, img.Height);
                    spriteProps.Add(new SpriteInfo(kvp.Key.Name.Replace(kvp.Key.Extension, ""), xCoord, 0, img.Width, img.Height));
                    xCoord += (img.Width + padding);
                }
            }

            return new KeyValuePair<Bitmap, List<SpriteInfo>>(sprite, spriteProps);
        }
    }

    /// <summary>
    /// Create StyleSheet with background positioning for each image
    /// </summary>
    /// <param name="base64SpriteSheet"></param>
    /// <param name="kvp"></param>
    /// <returns></returns>
    private static string GenerateStyleSheet(string base64SpriteSheet, KeyValuePair<Bitmap, List<SpriteInfo>> kvp)
    {
        var sb = new StringBuilder();

        // sprite sheet
        sb.AppendFormat(".spriteSheet {{ display: inline-block; width: {0}px; height: {1}px; background: url('data:image/png;base64,{2}') no-repeat top left; }}",
            kvp.Key.Width, kvp.Key.Height, base64SpriteSheet);

        // descendants of sprite sheet
        kvp.Value.Aggregate(sb, (a, b) => a.AppendLine(string.Format(".spriteSheet.{0} {{ background-position: -{1}px {2}px; width: {3}px; height: {4}px; {5} }} ", 
            b.Name, b.X, b.Y, b.W, b.H, (b.Name.Contains("display_block")) ? "display: block;" : "")));

        return sb.ToString();
    }