Thanks for the post, Christian.
my question is how I do, I tried the following trick:
treenodeMovil.Text = "<acronym Title='Seleccione casilla para Actualizar'>" + fila1["patente"].ToString() + "</acronym>" +"<img src='/imagenes/verde.png' alt='' style='order-width:0;' title='Disponible'>";
but with this option,three things happen:
1. checkbox should appear in the position of the image and the image in the checkbox.
how do I change the positions of the image and the checkbox?.
2. I am not using ImageUrl treenode property .
3. Tooltip appears when I have the mause on the node text and ideally show the tooltip on checkbox.
how I can solve it?