diff --git a/src/core/evaluator.js b/src/core/evaluator.js
index 05e033244..7b101d30a 100644
--- a/src/core/evaluator.js
+++ b/src/core/evaluator.js
@@ -605,6 +605,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         });
 
         if (imageRef) {
+          assert(!isInline, "Cannot cache an inline image globally.");
           this.globalImageCache.addPageIndex(imageRef, this.pageIndex);
 
           if (cacheGlobally) {