Asp.net 如何在使用bmp.Save（Response.OutputStream，

我正在创建一个定位程序。它创建了一个项目在仓库中位置的蓝图

Dim Storewidth As Integer = 1200
Dim StoreHeight As Integer = 800

Response.Clear()

Dim bmp As Bitmap = New Bitmap(Storewidth, StoreHeight, PixelFormat.Format24bppRgb)
Dim g As Graphics = Graphics.FromImage(bmp)
Dim a As Integer = 1 'for a counter to place number down the aisle to show location more clearer
g.TextRenderingHint = TextRenderingHint.AntiAlias

'background
g.Clear(Color.DarkGray)

'draw rectangle 
g.DrawRectangle(PenColor, X, Y, width, height)

'draw bitmap to the screen
bmp.Save(Response.OutputStream, ImageFormat.Jpeg)

g.Dispose()
bmp.Dispose()
Response.End()

上面的代码画了一个矩形。但是为了加快得到每个矩形的坐标，我想点击位图本身。有没有办法点击它刚刚创建的位图并返回X-Y坐标

附录：有没有一种方法可以在位图顶部覆盖网格之类的东西，然后单击它