Include data-original picture sources

Author: PrzemyslawKlys

OfficeIMO.Tests/Html.Images.cs

@@ -263,6 +263,40 @@ public void HtmlToWord_PictureSourceSet_UsesFirstAllowedImageCandidate() {
             Assert.Empty(options.Diagnostics);
         }
 
+        [Fact]
+        public void HtmlToWord_PictureSource_UsesDataOriginalBeforeImageFallback() {
+            var requested = new List<Uri>();
+            const string validPng = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8/x8AAwMCAO+/p9sAAAAASUVORK5CYII=";
+            using var httpClient = new HttpClient(new FakeHtmlHttpMessageHandler(request => {
+                requested.Add(request.RequestUri!);
+                return Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK) {
+                    Content = new ByteArrayContent(Convert.FromBase64String(validPng)) {
+                        Headers = {
+                            ContentType = new MediaTypeHeaderValue("image/png")
+                        }
+                    }
+                });
+            }));
+            var options = new HtmlToWordOptions {
+                HttpClient = httpClient
+            };
+            options.AllowedImageHosts.Add("images.example.test");
+            string html = """
+<picture>
+  <source data-original="https://images.example.test/high.png">
+  <img src="https://images.example.test/fallback.png" alt="Lazy picture" />
+</picture>
+""";
+
+            var doc = html.LoadFromHtml(options);
+
+            Assert.Single(doc.Images);
+            var request = Assert.Single(requested);
+            Assert.Equal("images.example.test", request.Host);
+            Assert.Equal("/high.png", request.AbsolutePath);
+            Assert.Empty(options.Diagnostics);
+        }
+
         [Fact]
         public void HtmlToWord_ImageSourceSet_UsesResponsiveCandidateBeforeSourceFallback() {
             var requested = new List<Uri>();

OfficeIMO.Word.Html/Converters/HtmlToWordConverter.Images.cs

@@ -10,7 +10,7 @@ namespace OfficeIMO.Word.Html {
     internal partial class HtmlToWordConverter {
         private static readonly HtmlUrlPolicy ImageSourceResolutionPolicy = CreateImageSourceResolutionPolicy();
         private static readonly string[] WordImageSrcSetAttributes = { "srcset", "data-srcset", "data-original-srcset", "data-lazy-srcset" };
-        private static readonly string[] WordPictureSourceAttributes = { "src", "data-src", "data-original-src", "data-lazy-src" };
+        private static readonly string[] WordPictureSourceAttributes = { "src", "data-src", "data-original", "data-original-src", "data-lazy-src" };
 
         private void ProcessImage(IHtmlImageElement img, WordDocument doc, HtmlToWordOptions options, WordParagraph? currentParagraph, WordHeaderFooter? headerFooter) {
             var src = ResolveWordImageSource(img, options);