I am starting to use Slimsy 3.0.0-beta3. I am on Umbraco 8.5.3.

I am kind of copying the first Slimsy example on GitHub like so:

 <img src="@Url.GetCropUrl(Model.Hero, 323, 300, quality:30, furtherOptions:"&format=auto")"
             data-srcset="@Url.GetSrcSetUrls(Model.Hero, 323, 300)"
             data-src="@Url.GetCropUrl(Model.Hero, 323, 300)"
             sizes="auto" class="lazyload" />

The Hero property is an Image Cropper, as stated in the Slimsy example description. Excerpt from the modelbuilder generated file:

[ImplementPropertyType("hero")]
public Umbraco.Core.PropertyEditors.ValueConverters.ImageCropperValue Hero => this.Value<Umbraco.Core.PropertyEditors.ValueConverters.ImageCropperValue>("hero");

yet, this expression:

@Url.GetSrcSetUrls(Model.Hero, 323, 300)

gives me this error:

Error CS1503: Argument 2: cannot convert from 'Umbraco.Core.PropertyEditors.ValueConverters.ImageCropperValue' to 'Umbraco.Core.Models.PublishedContent.IPublishedContent'

What am I missing? May be I am misunderstanding this sentence of the example description:

Use this method for setting the crop dimensions in your Razor code, assumes your image cropper property alias is "umbracoFile"

I don't know what that sentence means in relationship to the example.

I am grateful for input - thank you!