diff --git a/tests/ByteStringBatcherTests.hs b/tests/ByteStringBatcherTests.hs
index 767591a2a5..5e753feb66 100644
--- a/tests/ByteStringBatcherTests.hs
+++ b/tests/ByteStringBatcherTests.hs
@@ -7,51 +7,71 @@ import qualified Data.ByteString.Lazy as L
 import Data.Int (Int64)
 import Data.List.NonEmpty (fromList)
 import Simplex.Chat.ByteStringBatcher
+import Simplex.Chat.Protocol (maxChatMsgSize)
 import Test.Hspec
 
 byteStringBatcherTests :: Spec
 byteStringBatcherTests = describe "ByteStringBatcher tests" $ do
+  testBatchingCorrectness
+  it "image x.msg.new and x.msg.file.descr should fit into single batch" testImageFitsSingleBatch
+
+testBatchingCorrectness :: Spec
+testBatchingCorrectness = describe "correctness tests" $ do
   runBatcherTest 8 ["a"] [] ["a"]
-  runBatcherTest 8 ["a","b"] [] ["[a,b]"]
+  runBatcherTest 8 ["a", "b"] [] ["[a,b]"]
   runBatcherTest 8 ["a", "b", "c"] [] ["[a,b,c]"]
   runBatcherTest 8 ["a", "bb", "c"] [] ["[a,bb,c]"]
-  runBatcherTest 8 ["a", "b", "c", "d"] [] ["[a,b,c]","d"]
-  runBatcherTest 8 ["a", "bb", "c", "d"] [] ["[a,bb,c]","d"]
-  runBatcherTest 8 ["a", "bb", "c", "de"] [] ["[a,bb,c]","de"]
-  runBatcherTest 8 ["a", "b", "c", "d", "e"] [] ["[a,b,c]","[d,e]"]
+  runBatcherTest 8 ["a", "b", "c", "d"] [] ["[a,b,c]", "d"]
+  runBatcherTest 8 ["a", "bb", "c", "d"] [] ["[a,bb,c]", "d"]
+  runBatcherTest 8 ["a", "bb", "c", "de"] [] ["[a,bb,c]", "de"]
+  runBatcherTest 8 ["a", "b", "c", "d", "e"] [] ["[a,b,c]", "[d,e]"]
   runBatcherTest 8 ["aaaaa"] [] ["aaaaa"]
   runBatcherTest 8 ["8aaaaaaa"] [] ["8aaaaaaa"]
-  runBatcherTest 8 ["aaaa","bbbb"] [] ["aaaa","bbbb"]
-  runBatcherTest 8 ["aa","bbb","cc","dd"] [] ["[aa,bbb]","[cc,dd]"]
+  runBatcherTest 8 ["aaaa", "bbbb"] [] ["aaaa", "bbbb"]
+  runBatcherTest 8 ["aa", "bbb", "cc", "dd"] [] ["[aa,bbb]", "[cc,dd]"]
   runBatcherTest 8 ["9aaaaaaaa"] ["9aaaaaaaa"] []
-  runBatcherTest 8 ["aaaaa","bbb","cc"] [] ["aaaaa","[bbb,cc]"]
-  runBatcherTest 8 ["8aaaaaaa","bbb","cc"] [] ["8aaaaaaa","[bbb,cc]"]
-  runBatcherTest 8 ["9aaaaaaaa","bbb","cc"] ["9aaaaaaaa"] ["[bbb,cc]"]
-  runBatcherTest 8 ["9aaaaaaaa","bbb","cc","dd"] ["9aaaaaaaa"] ["[bbb,cc]","dd"]
-  runBatcherTest 8 ["9aaaaaaaa","bbb","cc","dd","e"] ["9aaaaaaaa"] ["[bbb,cc]","[dd,e]"]
-  runBatcherTest 8 ["bbb","cc","aaaaa"] [] ["[bbb,cc]","aaaaa"]
-  runBatcherTest 8 ["bbb","cc","8aaaaaaa"] [] ["[bbb,cc]","8aaaaaaa"]
-  runBatcherTest 8 ["bbb","cc","9aaaaaaaa"] ["9aaaaaaaa"] ["[bbb,cc]"]
-  runBatcherTest 8 ["bbb","cc","dd","9aaaaaaaa"] ["9aaaaaaaa"] ["[bbb,cc]","dd"]
-  runBatcherTest 8 ["bbb","cc","dd","e","9aaaaaaaa"] ["9aaaaaaaa"] ["[bbb,cc]","[dd,e]"]
-  runBatcherTest 8 ["bbb","cc","aaaaa","dd"] [] ["[bbb,cc]","aaaaa","dd"]
-  runBatcherTest 8 ["bbb","cc","aaaaa","dd","e"] [] ["[bbb,cc]","aaaaa","[dd,e]"]
-  runBatcherTest 8 ["bbb","cc","8aaaaaaa","dd"] [] ["[bbb,cc]","8aaaaaaa","dd"]
-  runBatcherTest 8 ["bbb","cc","8aaaaaaa","dd","e"] [] ["[bbb,cc]","8aaaaaaa","[dd,e]"]
-  runBatcherTest 8 ["bbb","cc","9aaaaaaaa"] ["9aaaaaaaa"] ["[bbb,cc]"]
-  runBatcherTest 8 ["bbb","cc","9aaaaaaaa","dd"] ["9aaaaaaaa"] ["[bbb,cc]","dd"]
-  runBatcherTest 8 ["bbb","cc","9aaaaaaaa","dd","e"] ["9aaaaaaaa"] ["[bbb,cc]","[dd,e]"]
-  runBatcherTest 8 ["9aaaaaaaa","10aaaaaaaa"] ["9aaaaaaaa","10aaaaaaaa"] []
-  runBatcherTest 8 ["8aaaaaaa","9aaaaaaaa","10aaaaaaaa"] ["9aaaaaaaa","10aaaaaaaa"] ["8aaaaaaa"]
-  runBatcherTest 8 ["9aaaaaaaa","8aaaaaaa","10aaaaaaaa"] ["9aaaaaaaa","10aaaaaaaa"] ["8aaaaaaa"]
-  runBatcherTest 8 ["9aaaaaaaa","10aaaaaaaa","8aaaaaaa"] ["9aaaaaaaa","10aaaaaaaa"] ["8aaaaaaa"]
-  runBatcherTest 8 ["bb","cc","dd","9aaaaaaaa","10aaaaaaaa"] ["9aaaaaaaa","10aaaaaaaa"] ["[bb,cc]","dd"]
-  runBatcherTest 8 ["bb","cc","9aaaaaaaa","dd","10aaaaaaaa"] ["9aaaaaaaa","10aaaaaaaa"] ["[bb,cc]","dd"]
-  runBatcherTest 8 ["bb","9aaaaaaaa","cc","dd","10aaaaaaaa"] ["9aaaaaaaa","10aaaaaaaa"] ["bb","[cc,dd]"]
-  runBatcherTest 8 ["bb","9aaaaaaaa","cc","10aaaaaaaa","dd"] ["9aaaaaaaa","10aaaaaaaa"] ["bb","cc","dd"]
-  runBatcherTest 8 ["9aaaaaaaa","bb","cc","dd","10aaaaaaaa"] ["9aaaaaaaa","10aaaaaaaa"] ["[bb,cc]","dd"]
-  runBatcherTest 8 ["9aaaaaaaa","bb","10aaaaaaaa","cc","dd"] ["9aaaaaaaa","10aaaaaaaa"] ["bb","[cc,dd]"]
-  runBatcherTest 8 ["9aaaaaaaa","10aaaaaaaa","bb","cc","dd"] ["9aaaaaaaa","10aaaaaaaa"] ["[bb,cc]","dd"]
+  runBatcherTest 8 ["aaaaa", "bbb", "cc"] [] ["aaaaa", "[bbb,cc]"]
+  runBatcherTest 8 ["8aaaaaaa", "bbb", "cc"] [] ["8aaaaaaa", "[bbb,cc]"]
+  runBatcherTest 8 ["9aaaaaaaa", "bbb", "cc"] ["9aaaaaaaa"] ["[bbb,cc]"]
+  runBatcherTest 8 ["9aaaaaaaa", "bbb", "cc", "dd"] ["9aaaaaaaa"] ["[bbb,cc]", "dd"]
+  runBatcherTest 8 ["9aaaaaaaa", "bbb", "cc", "dd", "e"] ["9aaaaaaaa"] ["[bbb,cc]", "[dd,e]"]
+  runBatcherTest 8 ["bbb", "cc", "aaaaa"] [] ["[bbb,cc]", "aaaaa"]
+  runBatcherTest 8 ["bbb", "cc", "8aaaaaaa"] [] ["[bbb,cc]", "8aaaaaaa"]
+  runBatcherTest 8 ["bbb", "cc", "9aaaaaaaa"] ["9aaaaaaaa"] ["[bbb,cc]"]
+  runBatcherTest 8 ["bbb", "cc", "dd", "9aaaaaaaa"] ["9aaaaaaaa"] ["[bbb,cc]", "dd"]
+  runBatcherTest 8 ["bbb", "cc", "dd", "e", "9aaaaaaaa"] ["9aaaaaaaa"] ["[bbb,cc]", "[dd,e]"]
+  runBatcherTest 8 ["bbb", "cc", "aaaaa", "dd"] [] ["[bbb,cc]", "aaaaa", "dd"]
+  runBatcherTest 8 ["bbb", "cc", "aaaaa", "dd", "e"] [] ["[bbb,cc]", "aaaaa", "[dd,e]"]
+  runBatcherTest 8 ["bbb", "cc", "8aaaaaaa", "dd"] [] ["[bbb,cc]", "8aaaaaaa", "dd"]
+  runBatcherTest 8 ["bbb", "cc", "8aaaaaaa", "dd", "e"] [] ["[bbb,cc]", "8aaaaaaa", "[dd,e]"]
+  runBatcherTest 8 ["bbb", "cc", "9aaaaaaaa"] ["9aaaaaaaa"] ["[bbb,cc]"]
+  runBatcherTest 8 ["bbb", "cc", "9aaaaaaaa", "dd"] ["9aaaaaaaa"] ["[bbb,cc]", "dd"]
+  runBatcherTest 8 ["bbb", "cc", "9aaaaaaaa", "dd", "e"] ["9aaaaaaaa"] ["[bbb,cc]", "[dd,e]"]
+  runBatcherTest 8 ["9aaaaaaaa", "10aaaaaaaa"] ["9aaaaaaaa", "10aaaaaaaa"] []
+  runBatcherTest 8 ["8aaaaaaa", "9aaaaaaaa", "10aaaaaaaa"] ["9aaaaaaaa", "10aaaaaaaa"] ["8aaaaaaa"]
+  runBatcherTest 8 ["9aaaaaaaa", "8aaaaaaa", "10aaaaaaaa"] ["9aaaaaaaa", "10aaaaaaaa"] ["8aaaaaaa"]
+  runBatcherTest 8 ["9aaaaaaaa", "10aaaaaaaa", "8aaaaaaa"] ["9aaaaaaaa", "10aaaaaaaa"] ["8aaaaaaa"]
+  runBatcherTest 8 ["bb", "cc", "dd", "9aaaaaaaa", "10aaaaaaaa"] ["9aaaaaaaa", "10aaaaaaaa"] ["[bb,cc]", "dd"]
+  runBatcherTest 8 ["bb", "cc", "9aaaaaaaa", "dd", "10aaaaaaaa"] ["9aaaaaaaa", "10aaaaaaaa"] ["[bb,cc]", "dd"]
+  runBatcherTest 8 ["bb", "9aaaaaaaa", "cc", "dd", "10aaaaaaaa"] ["9aaaaaaaa", "10aaaaaaaa"] ["bb", "[cc,dd]"]
+  runBatcherTest 8 ["bb", "9aaaaaaaa", "cc", "10aaaaaaaa", "dd"] ["9aaaaaaaa", "10aaaaaaaa"] ["bb", "cc", "dd"]
+  runBatcherTest 8 ["9aaaaaaaa", "bb", "cc", "dd", "10aaaaaaaa"] ["9aaaaaaaa", "10aaaaaaaa"] ["[bb,cc]", "dd"]
+  runBatcherTest 8 ["9aaaaaaaa", "bb", "10aaaaaaaa", "cc", "dd"] ["9aaaaaaaa", "10aaaaaaaa"] ["bb", "[cc,dd]"]
+  runBatcherTest 8 ["9aaaaaaaa", "10aaaaaaaa", "bb", "cc", "dd"] ["9aaaaaaaa", "10aaaaaaaa"] ["[bb,cc]", "dd"]
+
+testImageFitsSingleBatch :: IO ()
+testImageFitsSingleBatch = do
+  -- 14000 (limit for encoded image used in UI)
+  -- + 300 (remaining x.msg.new metadata, rounded up, actual example was 266)
+  let xMsgNewRoundedSize = 14300
+  -- size of x.msg.file.descr body for a file of size
+  -- 261_120 bytes (MAX_IMAGE_SIZE in UI), rounded up, example was 743
+  let descrRoundedSize = 800
+
+  let xMsgNewStr = L.replicate xMsgNewRoundedSize 1
+      descrStr = L.replicate descrRoundedSize 2
+
+  runBatcherTest' maxChatMsgSize [xMsgNewStr, descrStr] [] ["[" <> xMsgNewStr <> "," <> descrStr <> "]"]
 
 runBatcherTest :: Int64 -> [L.ByteString] -> [L.ByteString] -> [L.ByteString] -> SpecWith ()
 runBatcherTest batchLenLimit bStrs expectedLargeStrs expectedBatchedStrs =
@@ -60,8 +80,11 @@ runBatcherTest batchLenLimit bStrs expectedLargeStrs expectedBatchedStrs =
         <> (show (length expectedLargeStrs) <> " large, ")
         <> (show (length expectedBatchedStrs) <> " batches")
     )
-    $ do
-      let (largeStrs, batches) = partitionBatches $ batchByteStringObjects batchLenLimit (fromList bStrs)
-          batchedStrs = map (\(BSBatch batchBuilder _) -> BB.toLazyByteString batchBuilder) batches
-      largeStrs `shouldBe` expectedLargeStrs
-      batchedStrs `shouldBe` expectedBatchedStrs
+    (runBatcherTest' batchLenLimit bStrs expectedLargeStrs expectedBatchedStrs)
+
+runBatcherTest' :: Int64 -> [L.ByteString] -> [L.ByteString] -> [L.ByteString] -> IO ()
+runBatcherTest' batchLenLimit bStrs expectedLargeStrs expectedBatchedStrs = do
+  let (largeStrs, batches) = partitionBatches $ batchByteStringObjects batchLenLimit (fromList bStrs)
+      batchedStrs = map (\(BSBatch batchBuilder _) -> BB.toLazyByteString batchBuilder) batches
+  largeStrs `shouldBe` expectedLargeStrs
+  batchedStrs `shouldBe` expectedBatchedStrs