You can add the image in your toolbar by using the title attribute. Here is some modified code from one of my apps doing just this. Also, by defining a custom class you can assign a custom xtype and reuse the main toolbar... Either way the code should have what you are looking for:
Ext.define('myApp.view.Maintoolbar', {
extend: 'Ext.Toolbar',
xtype: 'maintoolbar',
requires: [
//any necessary requirements
],
config: {
docked: 'top',
title: '<div style="text-align:center;"><img src="images/logoSmall.png" width="185" height="36" alt="Company Name"></div>',
padding: '5 5 5 5',
items: [{
iconCls: 'arrow_down',
iconMask: true,
ui: 'normal',
//left: true,
text: 'Menu',
action: 'openmenu'
},{
xtype: 'spacer'
},{
xtype: 'button',
iconCls: 'arrow_down',
iconMask: true,
ui: 'normal',
align: 'right',
text: 'Logout',
action: 'logout'
}]
},
initialize: function() {
this.callParent();
}
});