Strict warning: Only variables should be passed In Drupal 7. I am printing a cck field image to my page.tpl like this

&lt;?php print render(field_view_field('node', $node, 'field_slide_photo1', 
array('label'=&gt;'hidden'))); ?&gt;


and I get this error php  Strict warning: Only variables should be passed by reference in include() (line 59 of var/www/html/upgrade2a/sites/all/themes/themea/page.tpl.php

But I can use this in node.tp with out errors?
    print render($content['field_upload_thumbnail']);

How do a print a field that is available in the page template?
You should attrubute the result of function to variable and then pass to render. The difference is that in sencond case you're passing certain variable instead of result of function.