gridview checkbox image insert mysql

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C#

I know how to upload and insert images using FileUpload ToolBox control.
But this time I have to insert selected gridView item(an image) to mysql using asp.net. So First I select an image from gridview then I insert that image to 'image' table. Problem is Mysql Workbench can't open the inserted image. I predict the inserted data is not a blob data.
And I think I'm missing some basic concepts of image insert.
My codes are given below.
Image data type is blob.
How can I fix it?
Examples will be much appriciated.
Thanks.

protected void ImageInsert()
    {
        {
            MySqlConnection con = new MySqlConnection(constr);
            MySqlCommand cmd = new MySqlCommand("INSERT INTO Images(Image) VALUES ('"+CheckBox().ToString()+"')", con);
            con.Open();
            int s1 = cmd.ExecuteNonQuery();
            if (s1 > 0)
            {
                imgUp1.Text = "Image Uploaded succesfully!";
            }
            con.Close();
        }
    }
private string CheckBox()
    {
        string url=null;
        foreach (GridViewRow row in gvImages.Rows)
        {
            CheckBox chkBox = row.FindControl("chkRow") as CheckBox;
            if (chkBox !=null && chkBox.Checked)
            {
                Image img = (Image)row.Cells[1].Controls[1];
                url = img.ImageUrl;
            }
        }
        return url;
    }</pre>