Unity图片转存及读取

[code]csharpcode：

/// <summary>
	/// 加载图片
	/// </summary>
	private Sprite LoadTexture(string url){
		using (Bitmap bitmap = new Bitmap(url))
		{
			Bitmap bmp = new Bitmap(bitmap, 256, 256);
			bitmap.Dispose();
			bmp.Save(Application.streamingAssetsPath + "/1.bmp", System.Drawing.Imaging.ImageFormat.Png);
		}

		//创建文件读取流
		FileStream fileStream = new FileStream(Application.streamingAssetsPath + "/1.bmp", FileMode.Open, FileAccess.Read);
		//创建文件长度缓冲区
		byte[] bytes = new byte[fileStream.Length];
		//读取文件
		fileStream.Read(bytes, 0, (int)fileStream.Length);
		//释放文件读取流
		fileStream.Close();
		//释放本机屏幕资源
		fileStream.Dispose();
		//创建Texture
		int width = 256;
		int height = 256;
		Texture2D texture = new Texture2D(width, height, TextureFormat.ARGB32, true);
		texture.LoadImage(bytes);
		texture.Apply();
		Debug.Log(texture.format);
		//创建Sprite
		Sprite sprite = Sprite.Create(texture, new Rect(0, 0, texture.width, texture.height), new Vector2(0.5f, 0.5f));
		return sprite;
	}