Hi

I'm attempting my first production Umbraco website (7.6.4) and have a document type which includes a Media Picker for creating a Image slider.

Based on the Typed Example code for Media Picker I've got the following code working to display the images in the template.

                @{
                var typedMultiMediaPicker = Model.Content.GetPropertyValue<IEnumerable<IPublishedContent>>("images");
                foreach (var item in typedMultiMediaPicker)
                {
                    <div class="item">
                        <img src="@item.Url" alt="">
                        <div class="caption">
                            <div class="box">
                                <h2>@item.Name</h2>
                            </div>
                        </div>
                    </div>
                }
            }

However I've also added a custom Dropdown list property to the default Image media type called captionBackgroundColour. If I try to access the property using @item.CaptionBackgroundColour I get Umbraco.Core.Models.IPublishedContent' does not contain a definition for 'CaptionBackgroundColour' and no extension method 'CaptionBackgroundColour' accepting a first argument of type 'Umbraco.Core.Models.IPublishedContent' could be found (are you missing a using directive or an assembly reference?)

Can anyone offer a steer on where I'm going wrong?