Alloy.Models.photo.on

I'm doing a custom object query and wanting to use the photo URL to display the image inside a <TableViewRow> using <ImageView>. I get the following error:

"'undefined' is not an object (evaluating 'Alloy.Models.photo.on')";

<TableView dataCollection="provider">
    <TableViewRow id="row" onClick="doViewDetails">
        <ImageView id="rowImage" image="{photo.urls.square_75}" />
        <Label id="rowFirstName" text="{first_name}" />
        <Label id="rowLastName" text="{last_name}" />
    </TableViewRow>
</TableView>