public GraphicsCache Cache { get; }

Public ReadOnly Property Cache As GraphicsCache

public partial class MainForm : XtraForm {
    static readonly Image logo = new Bitmap("../../Images/DXLogo.png");

    public MainForm() {
        InitializeComponent();

        chartControl.CustomPaint += this.OnChartCustomPaint;
    }

    private void OnChartCustomPaint(object sender, CustomPaintEventArgs e) {
        if (!(e is DXCustomPaintEventArgs dxArgs)) return;
        dxArgs.Cache.DrawImage(logo, new Point(10, 10));
    }
}

Public Class Form1
    Private Shared ReadOnly logo As Image = New Bitmap("../../Images/DXLogo.png")

    Protected Overrides Sub OnLoad(e As EventArgs)
        MyBase.OnLoad(e)

        AddHandler ChartControl.CustomPaint, AddressOf OnChartCustomPaint
    End Sub

    Sub OnChartCustomPaint(ByVal sender As Object, ByVal e As CustomPaintEventArgs)
        Dim dxArgs = TryCast(e, DXCustomPaintEventArgs)
        If (dxArgs Is Nothing) Then Return
        dxArgs.Cache.DrawImage(logo, New Point(10, 10))
    End Sub
End Class