Note, that theme img tag can handle all the attributes of standard HTML 'img' tag, such as align, border, etc.

Link to the internal image:

Code:

1

<%= img src: '/images/email.png', alt: 'email image' %>

Result:

Link to the external image:

Code:

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<%= img src: 'http://cdn1.sysgears.com/images/grain/logo-cacd6d0f221a8f8cab3c46db5b0e730a.png', height: 100, width: 200 %>

Result: