Custom Popup with Image

YOURViewModel Class

public class YOURPopupVM : ViewModel
{
    private string _title;
    private string _smallText;
    private string _spriteName;

    public YOURPopupVM(string title, string smallText, string spriteName)
    {

        this.Title = title;
        this.SmallText = smallText;
        this.SpriteName = spriteName;
    }

    public void Close()
    {
        YOURBehaviour.DeletePopupVMLayer();
    }

    public void Refresh()
    {
        this.Title = _title;
        this.SmallText = _smallText;
        this.SpriteName = _spriteName;
    }


    public string Title
    {
        get
        {
            return this._title;
        }
        set
        {
            this._title = value;
            base.OnPropertyChangedWithValue(value, "PopupTitle");
        }
    }

    public string SmallText
    {
        get
        {
            return this._smallText;
        }
        set
        {
            this._smallText = value;
            base.OnPropertyChangedWithValue(value, "PopupSmallText");
        }
    }

    public string SpriteName
    {
        get
        {
            return this._spriteName;
        }
        set
        {
            this._spriteName = value;
            base.OnPropertyChangedWithValue(value, "SpriteName");
        }
    }

}

YOURCampaignBehaviour Class

public class YOURBehaviour : CampaignBehaviorBase
{
    private static GauntletLayer _gauntletLayer;
    private static GauntletMovie _gauntletMovie;
    private static YOURPopupVM _popupVM;

    public static void CreatePopupVMLayer(string title, string smallText, string spriteName)
    {
        try
        {
            bool flag = YOURBehaviour._gauntletLayer != null;
            if (!flag)
            {
                YOURBehaviour._gauntletLayer = new GauntletLayer(1000, "GauntletLayer", false);
                bool flag2 = _popupVM == null;
                if (flag2)
                {
                    YOURBehaviour._popupVM = new YOURPopupVM(title, smallText, spriteName);
                }
                YOURBehaviour._gauntletMovie = (GauntletMovie)YOURBehaviour._gauntletLayer.LoadMovie("YOURPopupXMLFILENAME_WITHOUT_EXTENSION", YOURBehaviour._popupVM);
                YOURBehaviour._gauntletLayer.InputRestrictions.SetInputRestrictions(true, InputUsageMask.All);
                ScreenManager.TopScreen.AddLayer(YOURBehaviour._gauntletLayer);
                YOURBehaviour._gauntletLayer.IsFocusLayer = true;
                ScreenManager.TrySetFocus(YOURBehaviour._gauntletLayer);
                YOURBehaviour._popupVM.Refresh();   // does not work without this for me :(
            }
        }
        catch (Exception ex)
        {
            // do smthg
        }
    }


    public static void DeletePopupVMLayer()
    {
        ScreenBase topScreen = ScreenManager.TopScreen;
        bool flag = YOURBehaviour._gauntletLayer != null;
        if (flag)
        {
            YOURBehaviour._gauntletLayer.InputRestrictions.ResetInputRestrictions();
            YOURBehaviour._gauntletLayer.IsFocusLayer = false;
            bool flag2 = YOURBehaviour._gauntletMovie != null;
            if (flag2)
            {
                YOURBehaviour._gauntletLayer.ReleaseMovie(YOURBehaviour._gauntletMovie);
            }
            topScreen.RemoveLayer(YOURBehaviour._gauntletLayer);
        }
        YOURBehaviour._gauntletLayer = null;
        YOURBehaviour._gauntletMovie = null;
        YOURBehaviour._popupVM = null;
    }

Popup XML Prefab (YOURPopupXMLFILENAME.xml) - should be in ../GUI/Prefabs

<Prefab>
<Constants>
</Constants>
<Window>
    <Widget WidthSizePolicy="StretchToParent" HeightSizePolicy="StretchToParent" Sprite="BlankWhiteSquare_9" Color="#00000000">
        <Children>
            <!--Background-->
            <DimensionSyncWidget Id="SingleQueryPopupParent" WidthSizePolicy="Fixed" HeightSizePolicy="Fixed" SuggestedWidth="830" SuggestedHeight="650" HorizontalAlignment="Center" VerticalAlignment="Center" PositionYOffset="-20" DimensionToSync="Vertical">
                <Children>
                    <!-- background -->
                    <DimensionSyncWidget WidthSizePolicy="StretchToParent" HeightSizePolicy="StretchToParent" SuggestedWidth="830" ClipContents="true" DimensionToSync="Vertical">
                        <Children>
                            <Widget WidthSizePolicy="StretchToParent" HeightSizePolicy="StretchToParent" SuggestedWidth="830" SuggestedHeight="650" HorizontalAlignment="Center" VerticalAlignment="Top" Sprite="StdAssets\Popup\canvas" />

                            <!-- image -->
                            <ImageWidget WidthSizePolicy="Fixed" HeightSizePolicy="Fixed" HorizontalAlignment="Center" VerticalAlignment="Center" SuggestedWidth="600" SuggestedHeight="400" PositionYOffset="20" Sprite="@SpriteName"/>

                            <!-- image frame -->
                            <Widget WidthSizePolicy="Fixed" HeightSizePolicy="Fixed" HorizontalAlignment="Center" VerticalAlignment="Center" SuggestedWidth="600" SuggestedHeight="400" PositionYOffset="20" Sprite="frame_9" ExtendLeft="18" ExtendTop="18" ExtendRight="18" ExtendBottom="18" IsEnabled="false" />

                            <!-- text with big font -->
                            <!-- <TextWidget WidthSizePolicy="CoverChildren" HeightSizePolicy="CoverChildren" HorizontalAlignment="Center" VerticalAlignment="Center" PositionYOffset="-230" Text="@PopupBigText" /> -->

                            <!-- text with several lines -->
                            <!-- <RichTextWidget WidthSizePolicy="StretchToParent" HeightSizePolicy="CoverChildren" HorizontalAlignment="Center" PositionYOffset="60" MarginLeft="50" MarginRight="50" MarginTop="20" MarginBottom="20" Brush="Popup.Description.Text" MaxHeight="480" MinHeight="10" Text="@PopupMultiText" /> -->

                            <!-- text with small font -->
                            <TextWidget WidthSizePolicy="CoverChildren" HeightSizePolicy="CoverChildren" HorizontalAlignment="Center" VerticalAlignment="Center" PositionYOffset="-230" Brush="Popup.Description.Text" Text="@PopupSmallText" />

                            <!-- text on image
                            <TextWidget WidthSizePolicy="CoverChildren" HeightSizePolicy="CoverChildren" HorizontalAlignment="Center" VerticalAlignment="Center" PositionYOffset="150" Text="@PopupImageText" />-->

                            <!-- gradient from bottom to the top -->
                            <Widget WidthSizePolicy="StretchToParent" HeightSizePolicy="StretchToParent" Sprite="StdAssets\Popup\canvas_gradient" IsEnabled="false" />

                            <!--Close Button-->
                            <ListPanel WidthSizePolicy="CoverChildren" HeightSizePolicy="CoverChildren" HorizontalAlignment="Center" MarginTop="575">
                                <Children>
                                    <ButtonWidget WidthSizePolicy="Fixed" HeightSizePolicy="Fixed" SuggestedHeight="48" SuggestedWidth="240" HorizontalAlignment="Center" VerticalAlignment="Bottom" Brush="ButtonBrush1" Command.Click="Close" IsEnabled="true">
                                        <Children>
                                            <RichTextWidget DoNotAcceptEvents="true" WidthSizePolicy="CoverChildren" HeightSizePolicy="CoverChildren" HorizontalAlignment="Center" VerticalAlignment="Center" Brush="OverlayPopup.ButtonText" Brush.FontSize="20" Text="Continue" />
                                        </Children>
                                    </ButtonWidget>
                                </Children>
                            </ListPanel>
                        </Children>
                    </DimensionSyncWidget>

                    <!-- frame -->
                    <Widget WidthSizePolicy="StretchToParent" HeightSizePolicy="StretchToParent" Sprite="frame_9" ExtendLeft="18" ExtendTop="18" ExtendRight="18" ExtendBottom="18" IsEnabled="false" />

                    <!--title -->
                    <Widget WidthSizePolicy="Fixed" HeightSizePolicy="Fixed" SuggestedWidth="590" SuggestedHeight="125" HorizontalAlignment="Center" VerticalAlignment="Top" PositionXOffset="6" PositionYOffset="-28" Sprite="StdAssets\tabbar_popup" IsDisabled="true">
                        <Children>
                            <RichTextWidget WidthSizePolicy="CoverChildren" HeightSizePolicy="CoverChildren" HorizontalAlignment="Center" VerticalAlignment="Center" PositionYOffset="-16" Brush="Recruitment.Popup.Title.Text" Brush.FontSize="34" IsDisabled="true" Text="@PopupTitle" />
                        </Children>
                    </Widget>
                </Children>
            </DimensionSyncWidget>
        </Children>
    </Widget>
</Window>
</Prefab>

Make sure you have your sprite loaded properly into the game. Sprite's size in this example is 600x400.

Create popup with command:

YOURBehaviour.CreatePopupVMLayer("Hot Springs", "You stumble upon some beautiful hot springs. After bathing with your soldiers you feel fantastic!", "hot_springs");