feat(BurnPdfCommand): implement AddImageAnnotation with attachment handling

- Added logic to AddImageAnnotation to handle image attachments from a dictionary.
- Removed NotImplementedException placeholder for AddImageAnnotation with attachments.
- Refactored code to convert annotation bounds from pixels to inches before adding images.

EnvelopeGenerator.Application/Pdf/BurnPdfCommand.cs

@@ -305,7 +305,23 @@ public class BurnPdfCommandHandler : IRequestHandler<BurnPdfCommand>
 
     private void AddImageAnnotation(Annotation pAnnotation, Dictionary<string, Attachment> pAttachments)
     {
-        throw new NotImplementedException();
+        var oAttachment = pAttachments
+            .Where(a => a.Key == pAnnotation.ImageAttachmentId)
+            .SingleOrDefault();
+
+        if (oAttachment.Value == null)
+            return;
+
+        // Convert pixels to Inches
+        var oBounds = pAnnotation.Bbox.Select(ToInches).ToList();
+
+        var oX = oBounds[0];
+        var oY = oBounds[1];
+        var oWidth = oBounds[2];
+        var oHeight = oBounds[3];
+
+        _manager.SelectPage(pAnnotation.PageIndex + 1);
+        _manager.AddEmbeddedImageAnnotFromBase64(oAttachment.Value.Binary, (float)oX, (float)oY, (float)oWidth, (float)oHeight);
     }
 
     private void AddInkAnnotation(int page, string value)