issue replacing images with images using php and jquery

This is my PHP code for displaying the image:

<?php
        //reads in the file
        $file = file("pokedex.txt");

        foreach($file as $ind=>$line){
            $contains = stripos($line, "#");
            if ($contains === false) {
                echo "<p>".$line."</p><br/>";
            } else {
                $i = $ind / 2;
                echo "<div class = 'picture-wrapper' id = 'picture-".$i."'>";
                echo "<img src = 'img/picture-".$i.".jpg' class = 'picture-icon'/>";
                echo "<span>".$line."</span></div>";
            }
        }

    ?>

where $i is the number of each image, I have 5 images and the line

echo "<img src = 'img/picture-".$i.".jpg' class = 'picture-icon'/>";

echoes out each image. The variable $i pertains to each image number. I have successfully been able to write code that turns each of the 5 images to one (same) image when the user hits a "pictureReturn" button:

$('[name="pictureReturn"]').click(function(){
    $(".picture-icon").attr("src", "img/picture.jpg");
    });

How do I use jquery so that when a user hits a "pictureShow" button, the image will change from picture.jpg to the original 5 pictures?: <img src = 'img/picture-".$i.".jpg' class = 'picture-icon'/>

Thanks!