diff --git a/sf-writer/include/ImageAssembler.hpp b/sf-writer/include/ImageAssembler.hpp
index 1f226ff..7197f38 100644
--- a/sf-writer/include/ImageAssembler.hpp
+++ b/sf-writer/include/ImageAssembler.hpp
@@ -3,10 +3,20 @@
 
 #include <atomic>
 
-#include "formats.hpp"
+#include "buffer_config.hpp"
 
 const uint64_t IA_EMPTY_SLOT_VALUE = 0;
 
+struct ImageMetadataBlock
+{
+    uint64_t pulse_id[core_buffer::BUFFER_BLOCK_SIZE];
+    uint64_t frame_index[core_buffer::BUFFER_BLOCK_SIZE];
+    uint32_t daq_rec[core_buffer::BUFFER_BLOCK_SIZE];
+    uint8_t is_good_image[core_buffer::BUFFER_BLOCK_SIZE];
+    uint64_t block_start_pulse_id;
+    uint64_t block_stop_pulse_id;
+};
+
 class ImageAssembler {
     const size_t n_modules_;
     const size_t image_buffer_slot_n_bytes_;