Mira mi código
<?php
$consult="";
$consult1="";
$consult2="";
$consult3="";
$consult4="";
$consult5="";
$consult6="";
require_once('ingreso_herramientas/conexion/conexionadmin.php');
$conta = 'SELECT MAX(num_ingreso) AS num_ingreso FROM registro_ingreso';
$bus = $conexion->query($conta);
if ($bus->num_rows > 0){
$fila = $bus->fetch_array();
$c = 1 + $fila["num_ingreso"];
}
for($i = 1; $i < $c; $i++){
}
$con = $conexion->query("SELECT * FROM registro_ingreso ORDER BY num_ingreso ASC");
if ($con->num_rows > 0 ){
while ($row1 = $con->fetch_array(MYSQLI_ASSOC)){
$consult .=" <option value='".$row1['num_ingreso']."'>".$row1['num_ingreso']."</option>";
$consult2 .=" <option value='".$row1['num_ingreso']."'>".$row1['nombre']."</option>";
?>
<script>
function mostrar(){
document.getElementById("'.$row1['num_ingreso'].'").style.display = "block";
}
function ocultar(){
var imagenes = document.querySelectorAll("#'.$row1['num_ingreso'].'");
for (var i = 0, total = imagenes.length; i < total; i++){
document.getElementById(imagenes[2]).style.display = "none";
}
}
</script>
<html>
<body>
<ul>
<li>Ingreso: <?php echo $row1['num_ingreso']; ?> </li>
Nombre: <?php echo $row1['nombre']; ?>
</ul>
<input type="button" id="btn" value=">" style="border:none; background-color:#ffffff;" onclick="mostrar()" ondblclick="ocultar()" /><br><div id="'.$row1['num_ingreso'].'"><img width='250' height='150' src='ingreso_herramientas/fotos_herramientas/<?php echo $row1['imagen'];?>' alt='imagen herramienta' /></div>
<?php
};
};
?>
</body>
</html>