diff --git a/src/serializer.h b/src/serializer.h
index fb5e15a..5e97219 100644
--- a/src/serializer.h
+++ b/src/serializer.h
@@ -703,6 +703,7 @@ public:
                 img.comp = 4;
                 img.width = rect.width();
                 img.height = rect.height();
+                img.size = pixels * 4;
                 img.data = std::make_unique<uint8_t[]>(pixels * 4);
                 auto out = reinterpret_cast<glm::u8vec4*>(img.data.get());
                 if (grayscale)