Is the focalpoint property declared as virtual?

If it is have you ensured that your api-call include expand=*, or possibly expand=yourFocalpointProperty?

The solution is to make sure that the image property is expanded. Then you will get all data from your image model, like alt-text, focal point, etc.

This link shows how to expand multiple levels of a content area:
https://docs.developers.optimizely.com/content-management-system/v1.5.0-content-delivery-api/docs/customizing-conversion-from-icontent-to-contentapimodel#example-expand-multiple-levels-of-nested-contentarea-property
You need to do something similar but for you Image properties.

/// <summary>
/// Makes a content reference always expanded when serialized for Content delivery API.
/// https://docs.developers.optimizely.com/content-management-system/v1.5.0-content-delivery-api/docs/customizing-conversion-from-icontent-to-contentapimodel
/// </summary>
[Serializable]
[PropertyDefinitionTypePlugIn(GUID = "f656760c-3ab9-445e-987b-19e38281c8c9")]
public class AlwaysExpandedContentReference : PropertyContentReference
{
    // Empty constructor should be present, otherwise it will cause exception during startup.
    public AlwaysExpandedContentReference() : base()
    {
    }

    public AlwaysExpandedContentReference(ContentReference contentReference) : base(contentReference)
    {
    }
}

/// <summary>
/// Property converter for ContentReference properties that always expands the content reference.
/// </summary>
public class ExpandContentReferencePropertyConverter : IPropertyConverter
{
    public IPropertyModel Convert(PropertyData propertyData, ConverterContext contentMappingContext)
    {
        var model = new ContentReferencePropertyModel(propertyData as PropertyContentReference, contentMappingContext);
        model.Expand(contentMappingContext.Language);

        return model;
    }
}

 It really shouldn't be this difficult... It would be nice to be able to set an attribute on your property that makes sure that it is always expanded.