It depends if you want to store a path to an image file or the image itself.
The path is stored as any other string.
The image must be stored as BLOB (Binary Large OBject). Read the image file into a
byte
buffer and store that:
byte[] buffer = File.ReadAllBytes(filename);
oleDbCommand.Parameters.AddWithValue("@photo", buffer);
[EDIT]
There is also an error in your UPDATE statement. It must be
"Update AllPrinting set qrimg=@qrimg where UserID=@UserID;"
instead of
"Update AllPrinting set qrimg=@qrimg where UserID=@UserID)"
[/EDIT]