diff --git a/src/AxaFrance.AxeExtended.HtmlReport/OverallReportBuilder.cs b/src/AxaFrance.AxeExtended.HtmlReport/OverallReportBuilder.cs
index fd67865..c840982 100644
--- a/src/AxaFrance.AxeExtended.HtmlReport/OverallReportBuilder.cs
+++ b/src/AxaFrance.AxeExtended.HtmlReport/OverallReportBuilder.cs
@@ -71,16 +71,16 @@ public OverallReportBuilder Build()
         /// </summary>
         /// <param name="fileName">the filename of export report, default value "index.html"</param>
         /// <returns>the complete path of report</returns>
-        /// <exception cref="NotImplementedException"></exception>
         public string Export(string fileName = null)
         {
             if (!hasBuilt) Build();
             string path = Options.OutputFolder ?? Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());
 
-            //clean the folder
-            if (Directory.Exists(path))
+
+            // if the outpur format is Zip. we need to create a sub-folder and zip the content of that folder.
+            if(Options.OutputFormat == OutputFormat.Zip)
             {
-                Directory.Delete(path, true);
+                path = Path.Combine(path, Guid.NewGuid().ToString());
             }
             Directory.CreateDirectory(path);
             int sequence = 1;
diff --git a/src/AxaFrance.AxeExtended.HtmlReport/PageReportBuilder.cs b/src/AxaFrance.AxeExtended.HtmlReport/PageReportBuilder.cs
index 2118733..248c62a 100644
--- a/src/AxaFrance.AxeExtended.HtmlReport/PageReportBuilder.cs
+++ b/src/AxaFrance.AxeExtended.HtmlReport/PageReportBuilder.cs
@@ -269,7 +269,7 @@ private string GenerateRuleSection(AxeResultEnhancedItem[] items, string path)
                     if (node.Screenshot != null)
                     {
                         Guid id = Guid.NewGuid();
-                        filename = id.ToString() + ".png";
+                        filename = id.ToString() + ".webp";
                         File.WriteAllBytes(Path.Combine(path, filename), node.Screenshot);
                     }
 
diff --git a/src/AxaFrance.AxeExtended.Selenium/AxeSeleniumHelper.cs b/src/AxaFrance.AxeExtended.Selenium/AxeSeleniumHelper.cs
index a94562b..dc6e5ea 100644
--- a/src/AxaFrance.AxeExtended.Selenium/AxeSeleniumHelper.cs
+++ b/src/AxaFrance.AxeExtended.Selenium/AxeSeleniumHelper.cs
@@ -7,6 +7,7 @@
 using System;
 using System.Collections.Generic;
 using System.Drawing;
+using System.IO;
 using System.Linq;
 using System.Xml.Linq;
 
@@ -112,11 +113,11 @@ private static byte[] ScreenShot(WebDriver driver, AxeResultNode node, PageRepor
                     {
                         element = driver.FindElement(By.XPath(xPath));
                     }
-                }catch(Exception ex)
+                }
+                catch (Exception ex)
                 {
                     //sometimes the cssSelector provided by axe can not be used by selenium.
                     //in this case can't make screenshot on the element.
-
                     Console.WriteLine("[A11y] Unable to get element from cssSelector or xPath");
                 }
             }
@@ -125,7 +126,7 @@ private static byte[] ScreenShot(WebDriver driver, AxeResultNode node, PageRepor
             {
                 try
                 {
-                    var screenshot = options.UseAdvancedScreenshot ? AdvancedScreenshot(driver, we, options) : we.GetScreenshot().AsByteArray;
+                    var screenshot = options.UseAdvancedScreenshot ? AdvancedScreenshot(driver, we, options) : ToWebpByteArray(we.GetScreenshot());
                     driver.SwitchTo().DefaultContent(); //goes back to default context (leaving iframes)
                     return screenshot;
                 }
@@ -140,16 +141,37 @@ private static byte[] ScreenShot(WebDriver driver, AxeResultNode node, PageRepor
             {
                 driver.SwitchTo().DefaultContent();
                 Console.WriteLine("[A11y] The element can not be converted to type WebElement for screenshot.");
-                return Array.Empty<byte>();                
+                return Array.Empty<byte>();
             }
 
 
         }
 
+        /// <summary>
+        /// Convert selenium screenshot in png format to webp format.
+        /// </summary>
+        /// <param name="screenshot">Selenium screenshot object.</param>
+        /// <returns>Byte array of an image in webp format</returns>
+        private static byte[] ToWebpByteArray(Screenshot screenshot)
+        {
+            //covert screenshot in png format to webp
+            using (SKBitmap bitmap = SKBitmap.Decode(screenshot.AsByteArray))
+            {
+                using (SKImage img = SKImage.FromBitmap(bitmap))
+                {
+                    using (SKData data = img.Encode(SKEncodedImageFormat.Webp, 80))
+                    {
+                        return data.ToArray();
+                    }
+                }
+            }
+
+        }
+
         private static byte[] AdvancedScreenshot(WebDriver driver, WebElement element, PageReportOptions options)
         {
             BringToView(element, driver);
-            var imageViewPort = driver.GetScreenshot();            
+            var imageViewPort = driver.GetScreenshot();
             var locatable = (ILocatable)element;
 
             var location = locatable.Coordinates.LocationInViewport; //location and size are for 100% dpi
@@ -189,7 +211,7 @@ private static byte[] MarkOnImage(Screenshot imageViewPort, Point location, Size
                             Style = SKPaintStyle.Stroke,
                             StrokeWidth = options.HighlightThickness
                         });
-                    using (var data = bitmap.Encode(SKEncodedImageFormat.Png, 100))
+                    using (var data = bitmap.Encode(SKEncodedImageFormat.Webp, 80))
                     {
                         return data.ToArray();
                     }
diff --git a/src/WebEngine.Test/UnitTests/Accessibility.cs b/src/WebEngine.Test/UnitTests/Accessibility.cs
index 5e7f6aa..3672826 100644
--- a/src/WebEngine.Test/UnitTests/Accessibility.cs
+++ b/src/WebEngine.Test/UnitTests/Accessibility.cs
@@ -109,6 +109,7 @@ public void AuditWithRGAAAndExportHtml()
                     .WithRgaaExtension()
                     .WithSelenium(driver).Build().Export();
                 Debug.WriteLine($"Report generated in {sw.Elapsed.TotalSeconds} seconds");
+                Debug.WriteLine($"Report {filename}");
                 Assert.IsTrue(File.Exists(filename));
             }
 
@@ -167,6 +168,7 @@ public void UserJourneyTest()
 
                 string report = builder.Build().Export();
                 Assert.IsTrue(File.Exists(report));
+                Console.WriteLine(report);
             }
         }