diff --git a/modules/interventi/actions.php b/modules/interventi/actions.php
index e708fa2dd..77d752d15 100644
--- a/modules/interventi/actions.php
+++ b/modules/interventi/actions.php
@@ -563,7 +563,7 @@ switch (post('op')) {
         if (directory($docroot.'/files/interventi')) {
             if (post('firma_base64') != '') {
                 // Salvataggio firma
-                $firma_file = 'firma_'.time().'.png';
+                $firma_file = 'firma_'.time().'.jpg';
                 $firma_nome = post('firma_nome');
 
                 $data = explode(',', post('firma_base64'));
diff --git a/modules/interventi/add_firma.php b/modules/interventi/add_firma.php
index e22fd45c5..bf2917d59 100644
--- a/modules/interventi/add_firma.php
+++ b/modules/interventi/add_firma.php
@@ -49,7 +49,7 @@ if (get('anteprima') !== null) {
 }
 
 ?>
-<form class="canvas" action="<?php echo $rootdir ?>/editor.php?id_module=<?php echo $id_module; ?>&id_record=<?php echo $id_record; ?>" method="post" id="form-firma">
+<form class="canvas" action="<?php echo $rootdir; ?>/editor.php?id_module=<?php echo $id_module; ?>&id_record=<?php echo $id_record; ?>" method="post" id="form-firma">
     <input type="hidden" name="op" value="firma">
     <input type="hidden" name="backto" value="record-edit">
 
@@ -90,7 +90,9 @@ if (get('anteprima') !== null) {
             saveButton = document.querySelector("[data-action=save]"),
             canvas = document.getElementById("canvas");
 
-        var signaturePad = new SignaturePad(canvas);
+        var signaturePad = new SignaturePad(canvas, {
+            backgroundColor: 'rgb(255,255,255)'
+        });
 
         function resizeCanvas() {
             image_data = signaturePad.toDataURL();
@@ -115,7 +117,7 @@ if (get('anteprima') !== null) {
             if (signaturePad.isEmpty()) {
                 alert("Please provide signature first.");
             } else {
-                image_data = signaturePad.toDataURL();
+                image_data = signaturePad.toDataURL("image/jpeg", 100);
                 $('#firma_base64').val(image_data);
             }
         });