Model Code:
public File <ActionName>() { ... }

<a>
<iframe>
File As Img
<img>

Model Code:
public IResource <ActionName>() { ... }

<a>
<iframe>
Resource As Img
<img>

Model Code:
public ResourceReference <ActionName>() { ... }

<iframe>
Resource Reference As Img
<img>

Model Code:
public String <ActionName>() { ... }

<a>
<iframe>
String As Img
<img>

Model Code:
public URI <ActionName>() { ... }

Uri
<a>
<iframe>
Uri As Img
<img>

Model Code:
public URL <ActionName>() { ... }

Url
<a>
<iframe>
Url As Img
<img>

Model Code:
public Url <ActionName>() { ... }

<iframe>
Wicket Url As Img
<img>