diff --git a/dicom-viewer/package.json b/dicom-viewer/package.json
index b83d8dc..4b68591 100644
--- a/dicom-viewer/package.json
+++ b/dicom-viewer/package.json
@@ -5,7 +5,7 @@
   "type": "module",
   "scripts": {
     "dev": "vite",
-    "build": "tsc && vite build && cp dist/index.js /home/ross/rad/rad/rad/static/dv3d/index.js",
+    "build": "tsc && vite build && cp dist/index.js /home/ross/penracourses/rad/rad/static/dv3d/index.js",
     "lint": "eslint . --ext ts,tsx --report-unused-disable-directives --max-warnings 0",
     "preview": "vite preview"
   },
diff --git a/dicom-viewer/src/App.tsx b/dicom-viewer/src/App.tsx
index d4a5893..d9e4c36 100644
--- a/dicom-viewer/src/App.tsx
+++ b/dicom-viewer/src/App.tsx
@@ -442,8 +442,18 @@ function App({ container_id, imageStacks, autoCacheStack, annotationJson, viewer
     const onError = (ev: ErrorEvent) => {
       try {
         const msg = ev && ev.message ? String(ev.message) : '';
-        if (msg.includes('releaseGraphicsResources') || msg.includes('openGLTexture')) {
-          console.error('Detected graphics resource error:', ev);
+        // Detect known rendering/WebGL-related errors and actor/colormap issues
+        if (
+          msg.includes('releaseGraphicsResources') ||
+          msg.includes('openGLTexture') ||
+          msg.includes('getDefaultActor') ||
+          msg.includes('setColormapGPU') ||
+          msg.includes("can't access property \"actor\"") ||
+          // generic rendering failure
+          msg.toLowerCase().includes('webgl') ||
+          msg.toLowerCase().includes('colormap')
+        ) {
+          console.error('Detected graphics/rendering error:', ev);
           setGraphicsErrorMessage(msg || null);
           setGraphicsErrorVisible(true);
         }
@@ -456,8 +466,16 @@ function App({ container_id, imageStacks, autoCacheStack, annotationJson, viewer
       try {
         const reason = (ev && (ev as any).reason) || '';
         const text = typeof reason === 'string' ? reason : (reason && reason.message) ? reason.message : String(reason);
-        if (text.includes('releaseGraphicsResources') || text.includes('openGLTexture')) {
-          console.error('Detected graphics resource rejection:', ev);
+        if (
+          text.includes('releaseGraphicsResources') ||
+          text.includes('openGLTexture') ||
+          text.includes('getDefaultActor') ||
+          text.includes('setColormapGPU') ||
+          text.includes("can't access property \"actor\"") ||
+          text.toLowerCase().includes('webgl') ||
+          text.toLowerCase().includes('colormap')
+        ) {
+          console.error('Detected graphics/rendering rejection:', ev);
           setGraphicsErrorMessage(text || null);
           setGraphicsErrorVisible(true);
         }
@@ -1402,47 +1420,51 @@ function App({ container_id, imageStacks, autoCacheStack, annotationJson, viewer
         dicomImageLoaderInit();
         // Register client-side image loader for external images (JPEG/PNG/blob/data)
         try {
-          imageLoader.registerImageLoader('external', async (imageId: string) => {
-            // imageId expected as 'external:<url>'
-            const url = imageId.replace(/^external:/, '');
-            const img = new Image();
-            img.crossOrigin = 'anonymous';
-            img.src = url;
-            await new Promise((resolve, reject) => {
-              img.onload = () => resolve(true);
-              img.onerror = (e) => reject(e);
-            });
+          imageLoader.registerImageLoader('external', (imageId: string) => {
+            const promise = (async () => {
+              // imageId expected as 'external:<url>'
+              const url = imageId.replace(/^external:/, '');
+              const img = new Image();
+              img.crossOrigin = 'anonymous';
+              img.src = url;
+              await new Promise((resolve, reject) => {
+                img.onload = () => resolve(true);
+                img.onerror = (e) => reject(e);
+              });
 
-            const w = img.naturalWidth || img.width;
-            const h = img.naturalHeight || img.height;
-            const canvas = document.createElement('canvas');
-            canvas.width = w;
-            canvas.height = h;
-            const ctx = canvas.getContext('2d');
-            if (!ctx) throw new Error('Unable to create canvas context');
-            ctx.drawImage(img, 0, 0, w, h);
-            const im = ctx.getImageData(0, 0, w, h);
+              const w = img.naturalWidth || img.width;
+              const h = img.naturalHeight || img.height;
+              const canvas = document.createElement('canvas');
+              canvas.width = w;
+              canvas.height = h;
+              const ctx = canvas.getContext('2d');
+              if (!ctx) throw new Error('Unable to create canvas context');
+              ctx.drawImage(img, 0, 0, w, h);
+              const im = ctx.getImageData(0, 0, w, h);
 
-            const image = {
-              imageId,
-              minPixelValue: 0,
-              maxPixelValue: 255,
-              slope: 1.0,
-              intercept: 0,
-              rows: h,
-              columns: w,
-              height: h,
-              width: w,
-              color: true,
-              rgba: true,
-              sizeInBytes: im.data.length,
-              getPixelData: () => im.data,
-              // Some Cornerstone APIs expect `getImageData` or `getCanvas` - provide canvas and ImageData
-              getImageData: () => im,
-              getCanvas: () => canvas,
-            } as any;
+              const image = {
+                imageId,
+                minPixelValue: 0,
+                maxPixelValue: 255,
+                slope: 1.0,
+                intercept: 0,
+                rows: h,
+                columns: w,
+                height: h,
+                width: w,
+                color: true,
+                rgba: true,
+                sizeInBytes: im.data.length,
+                getPixelData: () => im.data,
+                // Some Cornerstone APIs expect `getImageData` or `getCanvas` - provide canvas and ImageData
+                getImageData: () => im,
+                getCanvas: () => canvas,
+              } as any;
 
-            return image;
+              return image;
+            })();
+
+            return { promise };
           });
         } catch (e) {
           console.warn('Failed to register external image loader', e);