diff --git a/cmd/wallart-server/main.go b/cmd/wallart-server/main.go
index b6e30d8..19315f3 100644
--- a/cmd/wallart-server/main.go
+++ b/cmd/wallart-server/main.go
@@ -77,6 +77,11 @@ func handleUpload(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
+		if img.Bounds().Max.X != 8 || img.Bounds().Max.Y != 8 {
+			http.Error(w, "Invalid frame size", http.StatusBadRequest)
+			return
+		}
+
 		// Dump it to the raw file
 		for y := 0; y < 8; y++ {
 			for x := 0; x < 8; x++ {