<form method='GET' action='<?php echo $_SERVER[PHP_SELF];?>'>
<input name='l1' type='text' value='<?php echo $_GET[l1];?>'><br>
<input name='r1' type='text' value='<?php echo $_GET[r1];?>'><br>
<input name='r2' type='text' value='<?php echo $_GET[r2];?>'><br>
<input name='l2' type='text' value='<?php echo $_GET[l2];?>'><br>
<input type='submit' value='view'><p>
</form>
<?php
if (isset($_GET[l1]) && isset($_GET[r1]) && isset($_GET[r2]) && isset($_GET[l2])) {
for ($x = $_GET[r1]; $x <= $_GET[r2]; $x += 1) echo "<img width='100%' src='$_GET[l1]$x$_GET[l2]'>";
}
?>