function image_histo($im) {
	
	$image = valeurs_image_trans($im, "courbes", "gif");
	if (!$image) return("");

	$x_i = $image["largeur"];
	$y_i = $image["hauteur"];
	$im = $image["fichier"];
	$dest = $image["fichier_dest"];
	$creer = $image["creer"];

	if ($creer) {
		$im = $image["fonction_imagecreatefrom"]($im);
		$im_ = imagecreatetruecolor(258, 130);
		@imagealphablending($im_, false);
		@imagesavealpha($im_,true);
		$color_t = ImageColorAllocateAlpha( $im_, 255, 255, 255 , 0 );
		imagefill ($im_, 0, 0, $color_t);
		$col_poly = imagecolorallocate($im_,0,0,0);
		imagepolygon($im_, array ( 0, 0, 257, 0, 257, 129, 0,129 ), 4, $col_poly);

		for ($x = 0; $x < $x_i; $x++) {
			for ($y=0; $y < $y_i; $y++) {

				$rgb = ImageColorAt($im, $x, $y);
				$a = ($rgb >> 24) & 0xFF;
				$r = ($rgb >> 16) & 0xFF;
				$g = ($rgb >> 8) & 0xFF;
				$b = $rgb & 0xFF;

				$a = (127-$a) / 127;
				$a=1;
				
				$gris = round($a*($r+$g+$b) / 3);
				$r = round($a*$r);
				$g = round($a*$g);
				$b = round($a*$b);
				
				$val_gris[$gris] ++;
				$val_r[$r] ++;
				$val_g[$g] ++;
				$val_b[$b] ++;
			} 
		}
		$max = max( max($val_gris), max($val_r), max($val_g), max($val_b));
		$rapport = (127/$max);

		$gris = imagecolorallocate($im_, 160, 160, 160);
		for ($i = 0; $i < 256; $i++) {
			$val = 127 - round(max(0,$val_gris[$i]) * $rapport);			imageline ($im_, $i+1, 128, $i+1, $val+1, $gris);
		}
		$bleu = imagecolorallocate($im_, 0, 0, 255);
		for ($i = 0; $i < 256; $i++) {
			$val = 127 - round(max(0,$val_b[$i]) * $rapport);
			if ($i==0) imagesetpixel ($im_, $i+1, $val+1, $bleu);
			else imageline($im_, $i, $val_old+1, $i+1, $val+1, $bleu);
			$val_old = $val;
		}
		$green = imagecolorallocate($im_, 0, 255, 0);
		for ($i = 0; $i < 256; $i++) {
			$val = 127 - round(max(0,$val_g[$i]) * $rapport);
			if ($i==0) imagesetpixel ($im_, $i+1, $val+1, $green);
			else imageline($im_, $i, $val_old+1, $i+1, $val+1, $green);
			$val_old = $val;
		}
		$rouge = imagecolorallocate($im_, 255, 0, 0);
		for ($i = 0; $i < 256; $i++) {
			$val = 127 - round(max(0,$val_r[$i]) * $rapport);
			if ($i==0) imagesetpixel ($im_, $i+1, $val+1, $rouge);
			else imageline($im_, $i, $val_old+1, $i+1, $val+1, $rouge);
			$val_old = $val;
		}

		$image["fonction_image"]($im_, "$dest");
		imagedestroy($im_);
		imagedestroy($im);
	}

	return "<img src='$dest' style='width: 258px; height: 130px;'  />";
}