related to picturebox

Don't call Dispose as Suresh advised — this code does not take into account possible exceptions.

Do this:

(using Image foreImage = Image.FromFile(tbxForeImage.Text)) {
    //use foreImage here
} //foreImage.Dispose() will be called here even it exception is thrown

You should to it to all temporary objects implementing System.IDisposable.

Only if the object is used during the life time of the declaring class, dispose in the Dispose of the owner class, hierarchically. For a good example, look at System.Windows.Forms.Form.Dispose (which is not System.IDisposable.Dispose) and usage samples.

—SA