Check out this thread: http://world.episerver.com/Modules/Forum/Pages/Thread.aspx?id=80054&epslanguage=en

It occured to me that you might be using webforms. In that case:

The ImageControl is used when an image is rendered in an content area. If you need to change the markup for an image property (ContentReference with UiHint set to "Image"), you should be able to create a new user control, and use a template descriptor with the image tag:

    [TemplateDescriptor(TagString = "Image")]
    public partial class Image : PropertyControlBase<ContentReference>
    {

    }
}

Much like how it is done with the "StringList"

Thank you Per!

But my code is never hit by the debugger, not even in the constructor. The url to the images changes in the markup though, so something is happening. The url becomes the url to the content data and not the actual url that the handler needs to serve the BLOB.

My code looks like this:

[TemplateDescriptor(TagString = UIHint.Image)]
public partial class ImageControl : PropertyControlBase<ContentReference>
{
    public ImageControl()
    {
        var hitMe = true;
    }
}

I'm seeing some inconsistent behavior when trying this out myself. Sometimes it uses the default renderer, and sometimes it uses the one I have defined. However, could you try changing tag/UiHint to "Image2"? That seem to work for me. Not a great solution though

My control is not chosen, even if I change the tag in the control and then in the rendering settings on the property control. But when I do, this is rendered instead:

<span><a href="/Views/Blocks/Promos/13">13</a></span>

Which is not the image url or the url to the image data. The url is to the block where the image property is defined.

Ok, the url thing seems to be a caching issue. Removed the images from the properties and re-added them. Then the urls are correct, but are rendered as a link. And not still able to use my custom control.

That is strange. This seem to work for me:

In a standard alloy 7.5 web forms site:

1. Modifed JumbotronBlock:

        [UIHint("Image2")]
        public virtual ContentReference Image { get; set; }

2. Add new user control "Image.ascx"

 Control Language="C#" AutoEventWireup="true" CodeBehind="Image.ascx.cs" Inherits="EPiServer.Templates.Alloy.Views.Properties.Image" %>

<p>I can render anything here</p>

code behind:  

    [TemplateDescriptor(TagString = "Image2")]
    public partial class Image : PropertyControlBase<ContentReference>
    {

    }

3. "I can render anything here" is now rendered instead of the image. To render the Image I would have used the CurrentData object in the page load method, or something like that.

I think the reason why it wont work with the "image" tag is because of the PropertyImageReferenceControl, (EPiServer.Web.PropertyControls), which has a template descriptor set with the image tag.

Hmm I added the tag to the property control instead, if you add it to the content type, the editor can chose pages and other files as well. But it should pick up the tag from the property control.

I will do a test with another UIHint in the content model.

Alright, this is embarrassing. There was a merge issue and the property type was changed to Url instead of ContentReference! Now is my controled loaded!!! And it seems to work with the standard tag, UIHint.Image.

Ah. Great! Not sure why I had some inconsistent behavior when using the standard image tag though. It seemed the ordering of the registering of the built in property control and the custom property control changed from one restart of the site to another.