What is ImageResizer?

  • An IIS/ASP.NET HttpModule & image server. On-demand image manipulation, delivery, and optimization — with low latency — makes responsive images easy
  • An image processing library optimized and secured for server-side use
  • A framework and collection of 40+ plugins to accomplish most common web imaging needs.

ImageResizer has a very simple (and powerful) URL API.

Fit modes

Basic Installation Guide

Important!: The MVC Routing plugin is required on .NET4+

Install from NuGet

Nearly all ImageResizer plugins are on NuGet (33+). You can enable source symbols from symbolsource.org for an enhanced debugging experience.

Get the basics:

PM> Install-Package ImageResizer.WebConfig
PM> Install-Package ImageResizer.Plugins.DiskCache
PM> Install-Package ImageResizer.Plugins.PrettyGifs
PM> Install-Package ImageResizer.MvcWebConfig

Manual Plugin Installation

  1. In your project, add a reference to the plugin DLL (or project, if you're using the source).
  2. Configure the plugin to be installed at startup via (i) or (ii).
  3. In the <plugins /> section of Web.config, insert <add name="PluginName" />
  4. In Application_Start, create an instance of the plugin and install it.

c# new PluginName().Install(ImageResizer.Configuration.Config.Current);

You will need to add the appropriate namespace reference to access the plugin.

Most configuration and plugin installation issues can be resolved by checking ImageResizer’s self-diagnostics page. If your local website is running at http://localhost:5000/, then you should browse to http://localhost:5000/resizer.debug.ashx to access it. See the Troubleshooting page for more details.

Want the Source?

We use submodules - clone using either

git clone -b develop --recursive https://github.com/imazen/resizer

- or -

git clone https://github.com/imazen/resizer
git checkout develop
git submodule update --init --recursive

Make sure to add a project reference.

If you're contributing, make sure you start by checking out the develop branch, and then making your changes. See our CONTRIBUTING guide on GitHub.

We also publish source code with each release that you can get from the download page.