picture uploading

hi,
I have a form for uploading picture.As soon as the user selects a picture and clicks the submit button,I want to show a gif picture indicating that uploading is taking place.The picture should start uploading only after displaying the gif picture.Any suggestions.

Mabye you could use a layer.

Have it hidden and then when the user clicks the button it shows asking them to wait. ect...

Well,I also have ideas.But I was looking specifically for some code.Anyway thanks for your reply