diff --git a/memento-note/lib/ai/tools/pptx.tool.ts b/memento-note/lib/ai/tools/pptx.tool.ts
index 7609786..32309e1 100644
--- a/memento-note/lib/ai/tools/pptx.tool.ts
+++ b/memento-note/lib/ai/tools/pptx.tool.ts
@@ -1111,6 +1111,26 @@ RULES:
 
           if (spec.slides.length === 0) return { success: false, error: 'No slides provided' }
 
+          // Pre-fetch all image URLs server-side and convert to base64 data URIs.
+          // pptxgenjs on Node.js cannot reliably fetch authenticated or relative URLs,
+          // so we do it here where we have full server context.
+          for (const slide of spec.slides) {
+            if (!slide.imageUrl || slide.imageUrl.startsWith('data:')) continue
+            try {
+              const res = await fetch(slide.imageUrl, { signal: AbortSignal.timeout(8000) })
+              if (res.ok) {
+                const buf = await res.arrayBuffer()
+                const mime = res.headers.get('content-type') || 'image/png'
+                const b64 = Buffer.from(buf).toString('base64')
+                slide.imageUrl = `data:${mime};base64,${b64}`
+              } else {
+                slide.imageUrl = undefined  // failed: show placeholder text
+              }
+            } catch {
+              slide.imageUrl = undefined
+            }
+          }
+
           const pptx = buildPresentation(spec)
           const base64 = await pptx.write({ outputType: 'base64' }) as string