How to upload and resize an image in ASP.NET MVC using ImageResizer

Recently I was developing an API and a CMS for a mobile application and I was asked to store different versions of an image and then display them depending on the device’s screen density.

Doing some googling I ran into this cool library called ImageResizer.

It is a library that offers a set of photography tools such as red-eye correction, image cropping, white balance correction and image resizing.

In this post I will show you how to upload an image and store different size versions of it using ASP.NET MVC and the Managed API of ImageResizer.

First, we are going to create a new ASP.NET Web Application and install the ImageResizer library via NuGet package manager.

Captura de pantalla 2014-07-23 11.50.16

Figure 1. Download ImageResizer library through NuGet package manager.

When the download is completed, it’s time to add some HTML to our view to create a file upload input and a submit button.

@using (Html.BeginForm("Upload", "Home", FormMethod.Post, new { enctype = "multipart/form-data" }))
 {
     <div class="form-group">;
         <label for="file" class="control-label">Select an Image</label>;
         <input type="file" name="file" id="file" class="form-control" />
         <br/>
         <input type="submit" value="Upload" class="btn btn-default" />
     </div>;
 }

Next, add a new Action to the controller that receives an HttpPostedFileBase object as a parameter. This action will be responsible for handling the resizing and storage of the image.

public ActionResult Upload(HttpPostedFileBase file)
{
	if (file != null)
	{
		//Declare a new dictionary to store the parameters for the image versions.
		var versions = new Dictionary<string, string>();

		var path = Server.MapPath("~/Images/");

		//Define the versions to generate
		versions.Add("_small", "maxwidth=600&maxheight=600&format=jpg";);
		versions.Add("_medium", "maxwidth=900&maxheight=900&format=jpg");
		versions.Add("_large", "maxwidth=1200&maxheight=1200&format=jpg");

		//Generate each version
		foreach (var suffix in versions.Keys)
		{
			file.InputStream.Seek(0, SeekOrigin.Begin);

			//Let the image builder add the correct extension based on the output file type
			ImageBuilder.Current.Build(
				new ImageJob(
					file.InputStream,
					path + file.FileName + suffix,
					new Instructions(versions[suffix]),
					false,
					true));
		}
	}

	return RedirectToAction("Index");
}

In order to resize the images, I used the Build()method of the ImageBuilder class. This method receives an ImageJob object that is initialized with five parameters:

  • A Stream object that contains our image file.
  • The destination path.
  • An Instructions object that contains the image processing parameters.
  • A boolean indicating if the source is disposed after being used.
  • A boolean indicating that the appropriate extension will be added to the destination path.

That’s it, now when you upload an image, you will notice that three versions are saved to the destination path that we specified.

If you need more information about the ImageResizer library you can check the documentation here.

I made this example based on the information presented at this page.

Setting up Umbraco with Visual Studio

Umbraco is a very powerful, very flexible, open-source CMS for .NET.It is a great tool when developing web sites and even services for things like mobile apps but, like with every new tool, it takes some time and effort to learn how to use it properly.

But believe me, once you overcome those scary hours of going through tutorials and documents, you will see how easy it is to work with this wonderful tool.

In this series, I will show you the basics of working with Umbraco, things I would have loved someone had told me on the first place.

This post is intended to serve as the starting point for other Umbraco posts I plan to write.

Creating a Visual Studio 2013 web application and setting up Umbraco

In order to start working with Umbraco, you need to create a new Web Application project.

Figure 1

Figure 1. Creating a new web application project.

Select an empty ASP.NET application project from the dialog and press OK.

Figure 2

Figure 2. Select an empty ASP.NET application template.

Now, in order to install Umbraco into your solution, open the NuGet package manager and search for “Umbraco”. Once the results appear, install the package called “Umbraco CMS”.

Figure 3

Figure 3. Installing Umbraco CMS from NuGet.

During the installation process, you will be asked if you want to overwrite the web.config file. This is because Umbraco adds several configuration values necessary for it to work. Select “No”,  Umbraco will overwrite your web.config file anyway, but it will create a backup in the App_Data folder. After the installation is finished you can merge your files and make sure they’re up to date.

Figure 4

Figure 4. Overwrite the web.config file.

Once the installation is done, you will notice that several folders were added to the project.

Figure 5

Figure 5. Solution Explorer.

Now, you need to setup your Umbraco site. To do this, run the solution with the browser of your preference. You will see a configuration screen with some fields you need to fill. Once you’re done click “Install” and wait for Umbraco to run the necessary tasks.

Figure 6

Figure 6. Umbraco installation screen.

This is it! Now you have Umbraco up and running in your solution.

Figure 7

Figure 7. Umbraco’s admin page.

Note. The installation process I followed in this post created a local data base. You can find the .sdf file in the App_Data folder, it is called Umbraco.sdf.

If you need to set up Umbraco to work with an SQL Server database, you can do so by clicking “Customize” in the setup page you were presented when you first ran the application. You will need to provide the server and database information.