sales_report_product_image/views/sale_product_view.xml

<?xml version="1.0" encoding="UTF-8"?>
<openerp>
    <data>

        <!-- Inherited sale order form view -->
        <record id="view_order_image_form_inherit" model="ir.ui.view">
            <field name="name">sale.order.form.sale.image</field>
            <field name="model">sale.order</field>
            <field name="inherit_id" ref="sale.view_order_form"/>
            <field name="arch" type="xml">
                <xpath expr="//page[@string='Order Lines']/field[@name='order_line']/form[@string='Sales Order Lines']/group/group/field[@name='product_id']" position="after">
                    <field name="image_medium" widget="image" string="Imagen"/>
                </xpath>

                <xpath expr="//page[@string='Order Lines']/field[@name='order_line']/tree[@string='Sales Order Lines']/field[@name='product_id']" position="after">
                    <field name="image_medium" widget="image" string="Imagen"/>
                </xpath>
                <field name="client_order_ref" position="after">
                    <field name="print_image"/>
                    <field name="image_sizes"/>
                </field>

            </field>
         </record>
    </data>
</openerp>