'Invalid image error :481' when displaying 7 charts or more as image

Dear friends,
Please be kindly requested to help me get over a problem in displaying charts (7 charts)as images in my userform .The problem is when navigating from image to image by using next and previous buttons I get this error "Invalid image 481" error and when debugging the cursor comes over this line which is highlited with yellow colour:

Image1.Picture = LoadPicture(Fname)

My function is as follows:

Private Sub SaveChart() Dim MyChart As Chart
Dim Fname As String


Set MyChart = Sheets("Charts").ChartObjects(ChartNum).Chart
'MyChart.Parent.Width = 400
'MyChart.Parent.Height = 350

Fname = ThisWorkbook.Path & Application.PathSeparator & "temp.gif"
MyChart.Export Filename:=Fname, FilterName:="GIF"



' Show the chart
Image1.Picture = LoadPicture(Fname)


End Sub

Could someone tell me where is the error ?

Following.........