wxpython display image

hi,

Please could you help me with displaying the png image file I am saving. I want it to display just after it is saved so within the same function onPLOT

import wx
import cx_Oracle
import datetime
import wx.grid
import csv
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.mlab as mlab
import matplotlib.ticker as ticker 
import cStringIO

class MainWindow(wx.Panel):
    def __init__(self,parent,id):
        wx.Panel.__init__(self,parent,id)

        self.background = wx.Panel(self)
          
        lblHeader = wx.StaticText(self,-1,label='PERF CALCULATION',pos=(100,10),style=wx.ALIGN_CENTER)
        font = wx.Font(15,wx.BOLD,wx.NORMAL,wx.ITALIC)
        lblHeader.SetFont(font)
               
        lblComboBox = wx.StaticText(self,-1,label='Fund_id:',pos=(5,65))
        self.Fund_id = wx.ComboBox(self, -1, pos=(120,60), size=(100,25), choices=['gip'], style=wx.CB_DROPDOWN)

        lblStartDate = wx.StaticText(self, -1, label='Start_date:', pos=(5,105))
        self.StartDate = wx.TextCtrl(self, -1, pos=(120,100), size=(100,25))

        lblEndDate = wx.StaticText(self,-1,label='End_date:',pos=(5,145))
        self.EndDate=wx.TextCtrl(self,-1,pos=(120,140),size=(100,25))

        self.myButton = wx.Button(self, label='Execute', pos=(50,200), size=(100,35))
        self.Bind(wx.EVT_BUTTON,self.OnExecute,id= self.myButton.GetId())
        
        self.myButton = wx.Button(self, label='Display', pos=(200,200), size=(100,35))
        self.Bind(wx.EVT_BUTTON,self.OnDisplay,id= self.myButton.GetId())
    
        self.Exit = wx.Button(self, label='Exit', pos=(350,200), size=(100,35))
        self.Bind(wx.EVT_BUTTON, self.OnExit, id=self.Exit.GetId())

        self.Clear = wx.Button(self,label='Clear',pos=(500,200),size=(100,35))
        self.Bind(wx.EVT_BUTTON,self.OnClear,id=self.Clear.GetId())

        self.Export = wx.Button(self,label='CSV Export',pos=(650,200),size=(100,35))
        self.Bind(wx.EVT_BUTTON,self.OnExport,id=self.Export.GetId())

        self.Plot = wx.Button(self,label='Plot Return',pos=(800,200),size=(100,35))
        self.Bind(wx.EVT_BUTTON,self.OnPlot,id=self.Plot.GetId())

        font1 = wx.Font(8,wx.MODERN,wx.NORMAL, wx.NORMAL, False)


        self.transferArea = wx.TextCtrl(self, pos=(20,250),size= (1200,600),style = wx.TE_READONLY |wx.TE_LEFT | wx.TE_MULTILINE)
        self.transferArea.SetFont(font1)
    
        self.dbresult = ''
    
    def OnExecute(self,event):
       # try:
        if self.dbresult != '':
           return self.result
        else:
        #   All the rest below
            connection = cx_Oracle.connect('/DB)
            cursor = connection.cursor()
            fund_id = self.Fund_id.GetValue()
            print fund_id
            start_date = self.StartDate.GetValue()
            print start_date
            end_date = self.EndDate.GetValue()
            print end_date
            sql ="""MY SQL"""% (str(start_date),str(end_date),str(fund_id))
            
            cursor.execute(sql) 
            
            result = []
            for line in cursor:
                line = [str(entry) for entry in line]
                result.append(line)
                
                
            self.result = result


    def OnDisplay(self,event):
        
        myheaderformat = "%-20s %-22s %-22s %-15s %-20s %13s %15s %12s"
        myreportformat = "%-20s %-22s %-22s %-15s %-20s %13s %15s %12s"
        
        header = myheaderformat % ('DATE','FUND_ID','STRATEGY','INSTRUMENT','SECTOR','PNL$M','NAV','PERFPCT')
        self.transferArea.WriteText(str(header+"\n"))
        
        for i in range(len(self.result)):
            myline = myreportformat % (self.result[i][0][0:-9],self.result[i][1],self.result[i][2],self.result[i][3],self.result[i][4],self.result[i][5],self.result[i][6],self.result[i][7])

            
            self.transferArea.WriteText(myline+"\n")


    def OnExit(self,event):
        self.Destroy()  # Close the frame.

    def OnClear(self,event):
        self.transferArea.Clear()

    def OnExport(self,event):
        filepath = 'gui.csv'
        csv_writer=csv.writer(open(filepath,"w"))
        title = ['DATE','FUND_ID','STRATEGY','INSTRUMENT','SECTOR','PNL$M','NAV','PERFPCT']
        csv_writer.writerow(title)
        for line in self.result:
            line = [str(entry)for entry in line]
            csv_writer.writerow(line)\


    def OnPlot(self,event):
        r = []

        d={}

        for line in self.result:
            line=tuple(line)
            r.append(line)
        r.sort()

        for line in r:
            key=line[0]
            d[key]=line[8]

        plot_list = [(i,d[i]) for i in d.keys()]
        
        plot_list.sort()

        x=[]
            
        for line in plot_list:
            dates = datetime.datetime.strptime(line[0], '%Y-%m-%d %H:%M:%S')
            x.append(dates) # append the dates to the x axis
                
        date = np.asarray(x)
                
        count=0
                
        y=[]
                
        for line in plot_list:
            count+=float(line[1])
            y.append(count) # append the results to y axis
        
        for line in x:
            print line
        
        for line in y:
            print line
            
        perf = np.asarray(y)
                    
        fig = plt.figure()
    
        ax = fig.add_subplot(111)
                    
                    #add some labels
        ax.set_ylabel('PERF IN %')
        ax.set_xlabel('Date')
        ax.set_title('Percentage Performance')
                    
        ax.plot(x,y,'s-')    # plot x y 
        fig.autofmt_xdate()
        
        #plt.show()
        plt.savefig("test.png")

        perf_plot = 'test.png'
             

app = wx.App()
frame = wx.Frame(None,-1,"TITLE")
MainWindow(frame,-1)
frame.Show(1)
app.MainLoop()