diff --git a/dicom-viewer/src/App.tsx b/dicom-viewer/src/App.tsx
index 4b75a05..72bd919 100644
--- a/dicom-viewer/src/App.tsx
+++ b/dicom-viewer/src/App.tsx
@@ -252,6 +252,18 @@ function App({ container_id, imageStacks, autoCacheStack, annotationJson, viewer
     return null;
   }
 
+  // Helper to detect external (non-DICOM) image ids
+  function isExternalImageId(imageId: string | null | undefined) {
+    if (!imageId) return false;
+    // Treat wadouri: as DICOM (our existing loader)
+    if (imageId.startsWith('wadouri:')) return false;
+    // blob: or data:image/ or common extensions
+    if (imageId.startsWith('blob:') || imageId.startsWith('data:image/')) return true;
+    const lower = imageId.toLowerCase();
+    if (lower.endsWith('.png') || lower.endsWith('.jpg') || lower.endsWith('.jpeg') || lower.endsWith('.gif')) return true;
+    return false;
+  }
+
   const [stackOrderModified, setStackOrderModified] = useState(false);
   const [loadingState, setLoadingState] = useState<null | "annotations" | "viewerState">(null);
   // Load annotations and viewer state from props if provided
@@ -446,6 +458,43 @@ function App({ container_id, imageStacks, autoCacheStack, annotationJson, viewer
       return;
     }
 
+    // If the chosen image is an external non-DICOM image, draw it to a canvas directly
+    if (isExternalImageId(chosenImageId)) {
+      try {
+        const img = new Image();
+        img.crossOrigin = 'anonymous';
+        img.src = chosenImageId as string;
+        await new Promise((resolve, reject) => {
+          img.onload = () => resolve(true);
+          img.onerror = (e) => reject(e);
+        });
+        const canvas = document.createElement('canvas');
+        const size = 160;
+        canvas.width = size;
+        canvas.height = size;
+        const ctx = canvas.getContext('2d');
+        if (ctx) {
+          // draw with aspect-fit
+          const ratio = Math.min(size / img.width, size / img.height);
+          const w = img.width * ratio;
+          const h = img.height * ratio;
+          const x = (size - w) / 2;
+          const y = (size - h) / 2;
+          ctx.fillStyle = '#000';
+          ctx.fillRect(0, 0, size, size);
+          ctx.drawImage(img, x, y, w, h);
+          const dataUrl = canvas.toDataURL('image/png');
+          setStackThumbnails(prev => ({ ...prev, [stackIdx]: dataUrl }));
+        } else {
+          setStackThumbnails(prev => ({ ...prev, [stackIdx]: 'BROKEN' }));
+        }
+      } catch (err) {
+        console.warn('generateThumbnail: failed to generate thumbnail for external image', err);
+        setStackThumbnails(prev => ({ ...prev, [stackIdx]: 'BROKEN' }));
+      }
+      return;
+    }
+
     const renderingEngine = renderingEngineRef.current;
     if (!renderingEngine) {
       console.warn('generateThumbnail: no renderingEngine yet for', stackIdx);
@@ -971,14 +1020,30 @@ function App({ container_id, imageStacks, autoCacheStack, annotationJson, viewer
 
     const fileArray = Array.from(files).sort((a, b) => a.name.localeCompare(b.name));
     let studyInstanceUID: string | undefined = undefined;
-    const arrayBuffer = await fileArray[0].arrayBuffer();
-    const dataSet = dicomParser.parseDicom(new Uint8Array(arrayBuffer));
-    studyInstanceUID = dataSet.string('x0020000d');
-    console.log("StudyInstanceUID:", studyInstanceUID);
 
-    const imageIds = fileArray.map(
-      file => `wadouri:${URL.createObjectURL(file)}`
-    );
+    // If the first file is likely a DICOM (no mime or .dcm extension), try to parse.
+    const firstFile = fileArray[0];
+    const isImageFile = firstFile.type && firstFile.type.startsWith('image/');
+    if (!isImageFile) {
+      try {
+        const arrayBuffer = await firstFile.arrayBuffer();
+        const dataSet = dicomParser.parseDicom(new Uint8Array(arrayBuffer));
+        studyInstanceUID = dataSet.string('x0020000d');
+        console.log("StudyInstanceUID:", studyInstanceUID);
+      } catch (e) {
+        // not DICOM or failed to parse; leave UID undefined
+        console.debug('handleFilesSelected: first file is not a DICOM or failed to parse', e);
+      }
+    }
+
+    // Create imageIds: use wadouri: for DICOM files, direct blob URLs for image files
+    const imageIds = fileArray.map((file) => {
+      const isImage = file.type && file.type.startsWith('image/');
+      if (isImage) {
+        return URL.createObjectURL(file);
+      }
+      return `wadouri:${URL.createObjectURL(file)}`;
+    });
 
     setAvailableStacks(prev => {
       const next = [...prev, { imageIds, studyInstanceUID }];
@@ -1205,7 +1270,33 @@ function App({ container_id, imageStacks, autoCacheStack, annotationJson, viewer
 
         if (viewportModes[i] === 'stack') {
           if (imageIds && imageIds.length > 0) {
-            viewport.setStack(imageIds);
+            // If this is an external (non-DICOM) image stack, render an <img> element as a fallback
+            const firstId = imageIds[0];
+            if (isExternalImageId(firstId)) {
+              try {
+                // Clear existing content and insert an image element
+                element.innerHTML = '';
+                const img = document.createElement('img');
+                img.style.width = '100%';
+                img.style.height = '100%';
+                img.style.objectFit = 'contain';
+                img.style.display = 'block';
+                img.src = firstId as string;
+                // allow drag to open in new tab etc.
+                img.setAttribute('draggable', 'false');
+                element.appendChild(img);
+                // Do not attach DICOM-specific tools to external images
+                mainToolGroup.removeViewports(renderingEngineId, viewportId);
+              } catch (err) {
+                console.warn('Failed to render external image in viewport', err);
+              }
+            } else {
+              try {
+                viewport.setStack(imageIds);
+              } catch (err) {
+                console.warn('viewport.setStack failed', err);
+              }
+            }
           }
           // CrosshairsTool is not applicable for stack viewports
           if (!crossHairsEnabled) {