Allan Thraen
Nov 9, 2011
(7 votes)

Use a workflow to resize images upon upload

Here’s a little timesaver for you all to enjoy. Usually when you work with the web, it’s important to ensure that you use images in the size. And typically that size is not the same as you get the pictures in. Naturally you can fire up photoshop and resize your images, or better yet, use the image editing tool in EPiServer CMS to do the same. However, that gets a bit tedious when you have a lot of images to resize, like I had recently. In fact, I had so many images that I needed to convert to two different sizes, that after the first 8 I gave up and figured “there’s got to be an easier way”. And voila! Why not use workflows to do the job for us?  Building custom workflows is no where as scary as it may sound – and the WF engine in .NET (with support in EPiServer as well) has a few advantages we can use here, like a build-in UI to set start parameters, attaching to file system events and a workflow engine to ensure async execution of multiple workflows.


First,  install from NuGet  (when available) or download the source code here.

When the workflow is installed either configure it in the episerver.config, by putting this in:

    <definition type="EPiServer.Labs.Workflows.ImageResize.ResizeImage,EPiServer.Labs.Workflows.ImageResize"
      name="Resize uploaded images" description="Will automatically resize images to your specifications" />


Or adding it manually in the Admin UI.



Once the workflow type has been configured (and saved) you are ready to attach it to an automatic start event – in this case it makes the most sense to attach to “FileCheckedIn” which happens whenever a new version of a file is checked in.



However, we only want to resize certain image files, so under “Start Parameters” we configure the virtual path they are under, a file mask, and the max height/width we want to generate. The workflow will always ensure the correct aspect ration.

You also define a new file name for the generated image, where {0} and {1} are used as placeholders for the old filename and old file extension.



When all this is done, you can just start uploading files and see how resized versions magically appear.



Nov 09, 2011


Hampus Persson
Hampus Persson Nov 9, 2011 03:50 PM


Nov 10, 2011 04:17 PM

Great way to use a workflow, will definitely try this out!

Nov 11, 2011 09:40 AM

Great! A standard workflow for the next release?

Jon Marks
Jon Marks Nov 11, 2011 04:52 PM

Wow! That is neat. Can you suggest any use cases for it?

Thomas Sløk Tvedt
Thomas Sløk Tvedt Jul 3, 2013 02:28 PM

Nice :-)
It would be even nicer if you copied the Unifiedfile-summary to the created files. In ResizeImage.cs, line 118, add something like:

var originalPath = File;
var originalUnifiedFile = HostingEnvironment.VirtualPathProvider.GetFile(originalPath) as UnifiedFile;
UnifiedFile.CopySummary(originalUnifiedFile, newfile);

mhmccabe Feb 11, 2014 05:11 PM

Is this source code compatible with EPiServer 7.5?

Snehal Ramteke
Snehal Ramteke Apr 3, 2017 11:38 AM

Is it compatiple with later versions of Episerver 7.5 and higher.

Please login to comment.
Latest blogs
Preview multiple Visitor Groups directly while browsing your Optimizely site

Visitor groups are great - it's an easy way to add personalization towards market segments to your site. But it does come with it's own set of...

Allan Thraen | Sep 26, 2022 | Syndicated blog

The Report Center is finally back in Optimizely CMS 12

With Episerver.CMS.UI 12.12.0 the Report Center is finally re-introduced in the core product.

Tomas Hensrud Gulla | Sep 26, 2022 | Syndicated blog

Dynamic Route in ASP.NET Core When MapDynamicControllerRoute Does Not Work

Background Creating one of the add-on for Optimizely I had to deal with challenge to register dynamically route for the API controller. Dynamic rou...

valdis | Sep 25, 2022 | Syndicated blog

404 Error on Static Assets Within an Optimizely plugin

Background With the move to CMS 12 and .NET 5/6, developers are now able to build Plugins and Extensions using Razor Class Libraries (RCL).  These...

Mark Stott | Sep 23, 2022