the code you are using is not fully right. a datagrid needs to have a source / dataprovider. i dont see that in your code.
you can create an array collection and using the object as your source
<mx:ArrayCollection id="myAC">
<mx:source>
<mx:Object theUrl="
http://kofi.com" theName="someName"/>
</mx:source>
</mx:ArrayCollection>
you then set your datagrids dataprovider to this arraycollection. one quick way to access your object is like this ( using binding )
{myAC.getItemAt(0).theName}
About your image. datagrids dont show images by default. you will have to create a custom renderer for your datagrid to show images. look into the documentation on how to create a datagrid item renderer.
Kofi