Warning: printf() [function.printf]: Too few arguments

Hi. I wanted to change my featured posts slideshow images from custom slides to category posts, because I want my recent posts to be displayed there. But this message shows up where my pictures should have been. The posts’ text and title are there, but the images aren’t. I saw different topics about this, and I tried everything they said there, but no good:

Warning: printf() [function.printf]: Too few arguments in /home/ziarulag/public_html/wp-content/themes/WpTech/includes/featuredposts/template.php on line 16

and this is line 16:

printf(“%s<img src=\”$slider[img]\” />%s”, ““, ““);