Increasing a number by one without truncating the beginning 0's

Hey all,
 
I have a problem, where i'm trying to find if a file exists, and if it does, update a textbox to the next number.  These filenames with either start with one or two zeros (they are from a digital camera) 
My code goes like this:
Dim filenumber Dim proc As New ProcessStartInfo filenumber = txtStart.Text Dim fFile As New FileInfo(lblWorkingDir.Text & "\DSC_" & filenumber & ".jpg") If fFile.Exists Then proc.Arguments = lblWorkingDir.Text & "\DSC_" & filenumber & ".jpg" proc.FileName = "c:\TinyImg.exe" Process.Start(proc) txtStart.Text = txtStart.Text.ToString + 1
 The number increment is working, but if i start with 0053, the next number it puts is just 54.  I need to keep the zeroes.
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