Handling images and on the fly re-sizing in DD4T

When it comes with DD4T we have plenty of control on the data and we can decided on how we wanted the page to be rendered.
The traditional approach of having difference size of same image is replaced in DD4T to have one single image and generate the thumbnail on the fly. In this approach, we will have only one image published in tridion, and rest will be created on the fly based on the request.

Just by adding below configuration on the web.config modules session will enable this feature
<modules runAllManagedModulesForAllRequests="true">
  <add name="BinaryModule" 
       type="DD4T.Web.Binaries.BinaryDistributionModule" />
 </modules>
The BinaryDistributionModule process the request as below

1. Process the Binary Request
2. Check if the file is already in the file system.
1. If file is available compare the last published date of the binary against the broker.
2. If the file is updated, update the existing file in the file system.
3. If the file is removed, delete the existing file in the file system.
3. If the file is not there in the file system.
1. Query the broker and create the file on local file system
4. Deliver the file.

The below Html helper method helps to generate thumbnails as below.
<img src="@Model.Fields["image"].LinkedComponentValues[0].Multimedia.Url.ResizeToWidth(150)" />
<img src="@Model.Fields["image"].LinkedComponentValues[0].Multimedia.Url.ResizeToWidthAndHeight(150,150)" />
This will generate the images as
<img src=" /images/sample_image_tcm4-102_w150.jpg" />
<img src=" /images/sample_image_tcm4-102_w150_h150.jpg" />

The width and height feature has a bug in the framework, you can extract the BinaryDistributionModule and BinaryFileManager Class from the DD4T.Web project and bit customization on the method "private string StripDimensions(string path, out Dimensions dimensions)" will solve the issue, This method can be found in BinaryFileManager.cs. Update this method as in below would work for both width and height.

	private string StripDimensions(string path, out Dimensions dimensions)
	{
	Regex re = new Regex(@"_(w(\d+))?(_h(\d+))?\.");
	if (re.IsMatch(path))
	{
	dimensions = new Dimensions();
	var match = re.Match(path);
	var dim = match.Groups[2].ToString();
	if (!String.IsNullOrEmpty(dim))
	{
	dimensions.Width = Convert.ToInt32(dim);
	}
	dim = match.Groups[4].ToString();
	if (!String.IsNullOrEmpty(dim))
	{
	dimensions.Height = Convert.ToInt32(dim);
	}
	return re.Replace(path, ".");
	}
	dimensions = null;
	return path;
	}

view raw BinaryFileManager.cs hosted with ❤ by GitHub

Later update the web.config to use the updated custom Binary Module, instead of default one,