C# と VB.NET の質問掲示板

書きなおしてみました。
そもそも論になりますが、画像はCellに入れるものではないですよね？
Shapes.AddPicture(@"c:\Penguins.jpg", Microsoft.Office.Core.MsoTriState.msoFalse, 
                                                 Microsoft.Office.Core.MsoTriState.msoTrue, 0, 0, 85, 15)
の引数にて、「0,0,85,15」で画像の左右上下の距離を指定してます。

using Microsoft.Office.Interop.Excel;
using System.Runtime.InteropServices;

Microsoft.Office.Interop.Excel.Application xApp = null;
Workbook xWb = null;
Worksheet xWs = null;
Range xRg = null;
Shapes xSp = null;
try
{
     xApp = new Microsoft.Office.Interop.Excel.Application();
     try
     {
          xWb = xApp.Workbooks.Open(@"c:\testX.xls", Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, 
                                    Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
          try
          {
               xWs = (Worksheet)xWb.ActiveSheet;
               try
               {
                    xRg = xWs.get_Range("A1", Type.Missing);
                    try
                    {
                         xSp = xWs.Shapes; 
                         xWs.Shapes.AddPicture(@"c:\Penguins.jpg", Microsoft.Office.Core.MsoTriState.msoFalse, 
                                                 Microsoft.Office.Core.MsoTriState.msoTrue, 0, 0, 85, 15);
                         xApp.Visible = true;
                    }
                    finally
                    {
                         Marshal.ReleaseComObject(xSp);
                    }
               }
               finally
               {
                    Marshal.ReleaseComObject(xRg);
               }
           }
           finally
           {
                Marshal.ReleaseComObject(xWs);
           }
     }
     finally
     {
            Marshal.ReleaseComObject(xWb);
     }
}
finally
{
       Marshal.ReleaseComObject(xApp);
}