diff --git a/addons/web/__manifest__.py b/addons/web/__manifest__.py
index 48b396a8946..1123c6d2114 100644
--- a/addons/web/__manifest__.py
+++ b/addons/web/__manifest__.py
@@ -390,6 +390,7 @@ This module provides the core of the Odoo Web Client.
             'web/static/src/js/libs/underscore.js',
             'web/static/src/js/libs/popper.js',
             'web/static/src/js/libs/zoomodoo.js',
+            'web/static/src/js/libs/jSignatureCustom.js',
             'web/static/src/js/chrome/keyboard_navigation_mixin.js',
             'web/static/src/js/core/abstract_service.js',
             'web/static/src/js/core/abstract_storage_service.js',
diff --git a/addons/web/static/src/js/libs/jSignatureCustom.js b/addons/web/static/src/js/libs/jSignatureCustom.js
new file mode 100644
index 00000000000..ca8306af286
--- /dev/null
+++ b/addons/web/static/src/js/libs/jSignatureCustom.js
@@ -0,0 +1,48 @@
+function _renderImageOnCanvas( data, formattype, rerendercallable ) {
+    'use strict'
+    // #1. Do NOT rely on this. No worky on IE 
+    //   (url max len + lack of base64 decoder + possibly other issues)
+    // #2. This does NOT affect what is captured as "signature" as far as vector data is 
+    // concerned. This is treated same as "signature line" - i.e. completely ignored
+    // the only time you see imported image data exported is if you export as image.
+
+    // we do NOT call rerendercallable here (unlike in other import plugins)
+    // because importing image does absolutely nothing to the underlying vector data storage
+    // This could be a way to "import" old signatures stored as images
+    // This could also be a way to import extra decor into signature area.
+
+    // Odoo override: 
+    // If a signature is saved in mobile resolution, when the user tries to sign a document in desktop, the size that is shown is the mobile size, which is strange for the user.
+    // This modifies the library method that adds the image to the canvas, resizing the image to the canvas size.
+    
+    var img = new Image()
+    // this = Canvas DOM elem. Not jQuery object. Not Canvas's parent div.
+    , c = this;
+
+    img.onload = function () {
+        var ctx = c.getContext("2d");
+        var oldShadowColor = ctx.shadowColor;
+        ctx.shadowColor = "transparent";
+        ctx.drawImage( 
+            img, 0, 0
+            , c.width
+            , c.height
+        );
+        ctx.shadowColor = oldShadowColor;
+    };
+
+    img.src = 'data:' + formattype + ',' + data;
+}
+
+// Supported image types
+const imageTypes = [
+    'image',
+    'image/png;base64',
+    'image/jpeg;base64',
+    'image/jpg;base64',
+];
+
+// Override
+for (const imageType of imageTypes) {
+    $.fn.jSignature("addPlugin", "import", imageType, _renderImageOnCanvas);
+}