diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index c27e4e820..31246d0b1 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -69,6 +69,7 @@ using namespace epee;
 #include "common/base58.h"
 #include "common/dns_utils.h"
 #include "common/notify.h"
+#include "common/perf_timer.h"
 #include "ringct/rctSigs.h"
 #include "ringdb.h"
 #include "device/device_cold.hpp"
@@ -10517,11 +10518,13 @@ crypto::public_key wallet2::get_tx_pub_key_from_received_outs(const tools::walle
 
 bool wallet2::export_key_images(const std::string &filename) const
 {
+  PERF_TIMER(export_key_images);
   std::vector<std::pair<crypto::key_image, crypto::signature>> ski = export_key_images();
   std::string magic(KEY_IMAGE_EXPORT_FILE_MAGIC, strlen(KEY_IMAGE_EXPORT_FILE_MAGIC));
   const cryptonote::account_public_address &keys = get_account().get_keys().m_account_address;
 
   std::string data;
+  data.reserve(ski.size() * (sizeof(crypto::key_image) + sizeof(crypto::signature)) + 2 * sizeof(crypto::public_key));
   data += std::string((const char *)&keys.m_spend_public_key, sizeof(crypto::public_key));
   data += std::string((const char *)&keys.m_view_public_key, sizeof(crypto::public_key));
   for (const auto &i: ski)
@@ -10531,6 +10534,7 @@ bool wallet2::export_key_images(const std::string &filename) const
   }
 
   // encrypt data, keep magic plaintext
+  PERF_TIMER(export_key_images_encrypt);
   std::string ciphertext = encrypt_with_view_secret_key(data);
   return epee::file_io_utils::save_string_to_file(filename, magic + ciphertext);    
 }
@@ -10538,6 +10542,7 @@ bool wallet2::export_key_images(const std::string &filename) const
 //----------------------------------------------------------------------------------------------------
 std::vector<std::pair<crypto::key_image, crypto::signature>> wallet2::export_key_images() const
 {
+  PERF_TIMER(export_key_images_raw);
   std::vector<std::pair<crypto::key_image, crypto::signature>> ski;
 
   ski.reserve(m_transfers.size());
@@ -10590,6 +10595,7 @@ std::vector<std::pair<crypto::key_image, crypto::signature>> wallet2::export_key
 
 uint64_t wallet2::import_key_images(const std::string &filename, uint64_t &spent, uint64_t &unspent)
 {
+  PERF_TIMER(import_key_images_fsu);
   std::string data;
   bool r = epee::file_io_utils::load_file_to_string(filename, data);
 
@@ -10603,6 +10609,7 @@ uint64_t wallet2::import_key_images(const std::string &filename, uint64_t &spent
 
   try
   {
+    PERF_TIMER(import_key_images_decrypt);
     data = decrypt_with_view_secret_key(std::string(data, magiclen));
   }
   catch (const std::exception &e)
@@ -10641,6 +10648,7 @@ uint64_t wallet2::import_key_images(const std::string &filename, uint64_t &spent
 //----------------------------------------------------------------------------------------------------
 uint64_t wallet2::import_key_images(const std::vector<std::pair<crypto::key_image, crypto::signature>> &signed_key_images, uint64_t &spent, uint64_t &unspent, bool check_spent)
 {
+  PERF_TIMER(import_key_images_lots);
   COMMAND_RPC_IS_KEY_IMAGE_SPENT::request req = AUTO_VAL_INIT(req);
   COMMAND_RPC_IS_KEY_IMAGE_SPENT::response daemon_resp = AUTO_VAL_INIT(daemon_resp);
 
@@ -10654,6 +10662,9 @@ uint64_t wallet2::import_key_images(const std::vector<std::pair<crypto::key_imag
     return 0;
   }
 
+  req.key_images.reserve(signed_key_images.size());
+
+  PERF_TIMER_START(import_key_images_A);
   for (size_t n = 0; n < signed_key_images.size(); ++n)
   {
     const transfer_details &td = m_transfers[n];
@@ -10667,20 +10678,24 @@ uint64_t wallet2::import_key_images(const std::vector<std::pair<crypto::key_imag
     const cryptonote::txout_to_key &o = boost::get<cryptonote::txout_to_key>(out.target);
     const crypto::public_key pkey = o.key;
 
-    std::vector<const crypto::public_key*> pkeys;
-    pkeys.push_back(&pkey);
-    THROW_WALLET_EXCEPTION_IF(!(rct::scalarmultKey(rct::ki2rct(key_image), rct::curveOrder()) == rct::identity()),
-        error::wallet_internal_error, "Key image out of validity domain: input " + boost::lexical_cast<std::string>(n) + "/"
-        + boost::lexical_cast<std::string>(signed_key_images.size()) + ", key image " + epee::string_tools::pod_to_hex(key_image));
-
-    THROW_WALLET_EXCEPTION_IF(!crypto::check_ring_signature((const crypto::hash&)key_image, key_image, pkeys, &signature),
-        error::signature_check_failed, boost::lexical_cast<std::string>(n) + "/"
-        + boost::lexical_cast<std::string>(signed_key_images.size()) + ", key image " + epee::string_tools::pod_to_hex(key_image)
-        + ", signature " + epee::string_tools::pod_to_hex(signature) + ", pubkey " + epee::string_tools::pod_to_hex(*pkeys[0]));
+    if (!td.m_key_image_known || !(key_image == td.m_key_image))
+    {
+      std::vector<const crypto::public_key*> pkeys;
+      pkeys.push_back(&pkey);
+      THROW_WALLET_EXCEPTION_IF(!(rct::scalarmultKey(rct::ki2rct(key_image), rct::curveOrder()) == rct::identity()),
+          error::wallet_internal_error, "Key image out of validity domain: input " + boost::lexical_cast<std::string>(n) + "/"
+          + boost::lexical_cast<std::string>(signed_key_images.size()) + ", key image " + epee::string_tools::pod_to_hex(key_image));
 
+      THROW_WALLET_EXCEPTION_IF(!crypto::check_ring_signature((const crypto::hash&)key_image, key_image, pkeys, &signature),
+          error::signature_check_failed, boost::lexical_cast<std::string>(n) + "/"
+          + boost::lexical_cast<std::string>(signed_key_images.size()) + ", key image " + epee::string_tools::pod_to_hex(key_image)
+          + ", signature " + epee::string_tools::pod_to_hex(signature) + ", pubkey " + epee::string_tools::pod_to_hex(*pkeys[0]));
+    }
     req.key_images.push_back(epee::string_tools::pod_to_hex(key_image));
   }
+  PERF_TIMER_STOP(import_key_images_A);
 
+  PERF_TIMER_START(import_key_images_B);
   for (size_t n = 0; n < signed_key_images.size(); ++n)
   {
     m_transfers[n].m_key_image = signed_key_images[n].first;
@@ -10688,9 +10703,11 @@ uint64_t wallet2::import_key_images(const std::vector<std::pair<crypto::key_imag
     m_transfers[n].m_key_image_known = true;
     m_transfers[n].m_key_image_partial = false;
   }
+  PERF_TIMER_STOP(import_key_images_B);
 
   if(check_spent)
   {
+    PERF_TIMER(import_key_images_RPC);
     m_daemon_rpc_mutex.lock();
     bool r = epee::net_utils::invoke_http_json("/is_key_image_spent", req, daemon_resp, m_http_client, rpc_timeout);
     m_daemon_rpc_mutex.unlock();
@@ -10713,6 +10730,7 @@ uint64_t wallet2::import_key_images(const std::vector<std::pair<crypto::key_imag
                                                   // was created by sweep_all, so we can't know the spent height and other detailed info.
   std::unordered_map<crypto::key_image, crypto::hash> spent_key_images;
 
+  PERF_TIMER_START(import_key_images_C);
   for (const transfer_details &td: m_transfers)
   {
     for (const cryptonote::txin_v& in : td.m_tx.vin)
@@ -10721,10 +10739,12 @@ uint64_t wallet2::import_key_images(const std::vector<std::pair<crypto::key_imag
         spent_key_images.insert(std::make_pair(boost::get<cryptonote::txin_to_key>(in).k_image, td.m_txid));
     }
   }
+  PERF_TIMER_STOP(import_key_images_C);
 
+  PERF_TIMER_START(import_key_images_D);
   for(size_t i = 0; i < signed_key_images.size(); ++i)
   {
-    transfer_details &td = m_transfers[i];
+    const transfer_details &td = m_transfers[i];
     uint64_t amount = td.amount();
     if (td.m_spent)
       spent += amount;
@@ -10742,6 +10762,8 @@ uint64_t wallet2::import_key_images(const std::vector<std::pair<crypto::key_imag
         spent_txids.insert(skii->second);
     }
   }
+  PERF_TIMER_STOP(import_key_images_D);
+
   MDEBUG("Total: " << print_money(spent) << " spent, " << print_money(unspent) << " unspent");
 
   if (check_spent)
@@ -10751,8 +10773,12 @@ uint64_t wallet2::import_key_images(const std::vector<std::pair<crypto::key_imag
     COMMAND_RPC_GET_TRANSACTIONS::response gettxs_res;
     gettxs_req.decode_as_json = false;
     gettxs_req.prune = false;
+    gettxs_req.txs_hashes.reserve(spent_txids.size());
     for (const crypto::hash& spent_txid : spent_txids)
       gettxs_req.txs_hashes.push_back(epee::string_tools::pod_to_hex(spent_txid));
+
+
+    PERF_TIMER_START(import_key_images_E);
     m_daemon_rpc_mutex.lock();
     bool r = epee::net_utils::invoke_http_json("/gettransactions", gettxs_req, gettxs_res, m_http_client, rpc_timeout);
     m_daemon_rpc_mutex.unlock();
@@ -10760,8 +10786,10 @@ uint64_t wallet2::import_key_images(const std::vector<std::pair<crypto::key_imag
     THROW_WALLET_EXCEPTION_IF(gettxs_res.status == CORE_RPC_STATUS_BUSY, error::daemon_busy, "gettransactions");
     THROW_WALLET_EXCEPTION_IF(gettxs_res.txs.size() != spent_txids.size(), error::wallet_internal_error,
       "daemon returned wrong response for gettransactions, wrong count = " + std::to_string(gettxs_res.txs.size()) + ", expected " + std::to_string(spent_txids.size()));
+    PERF_TIMER_STOP(import_key_images_E);
 
     // process each outgoing tx
+    PERF_TIMER_START(import_key_images_F);
     auto spent_txid = spent_txids.begin();
     hw::device &hwdev =  m_account.get_device();
     for (const COMMAND_RPC_GET_TRANSACTIONS::entry& e : gettxs_res.txs)
@@ -10857,7 +10885,9 @@ uint64_t wallet2::import_key_images(const std::vector<std::pair<crypto::key_imag
 
       ++spent_txid;
     }
+    PERF_TIMER_STOP(import_key_images_F);
 
+    PERF_TIMER_START(import_key_images_G);
     for (size_t n : swept_transfers)
     {
       const transfer_details& td = m_transfers[n];
@@ -10868,6 +10898,7 @@ uint64_t wallet2::import_key_images(const std::vector<std::pair<crypto::key_imag
       const crypto::hash &spent_txid = crypto::null_hash; // spent txid is unknown
       m_confirmed_txs.insert(std::make_pair(spent_txid, pd));
     }
+    PERF_TIMER_STOP(import_key_images_G);
   }
 
   return m_transfers[signed_key_images.size() - 1].m_block_height;
@@ -10955,6 +10986,7 @@ void wallet2::import_blockchain(const std::tuple<size_t, crypto::hash, std::vect
 //----------------------------------------------------------------------------------------------------
 std::vector<tools::wallet2::transfer_details> wallet2::export_outputs() const
 {
+  PERF_TIMER(export_outputs);
   std::vector<tools::wallet2::transfer_details> outs;
 
   outs.reserve(m_transfers.size());
@@ -10970,29 +11002,53 @@ std::vector<tools::wallet2::transfer_details> wallet2::export_outputs() const
 //----------------------------------------------------------------------------------------------------
 std::string wallet2::export_outputs_to_str() const
 {
-  std::vector<tools::wallet2::transfer_details> outs = export_outputs();
+  PERF_TIMER(export_outputs_to_str);
 
   std::stringstream oss;
   boost::archive::portable_binary_oarchive ar(oss);
-  ar << outs;
+  ar << m_transfers;
 
   std::string magic(OUTPUT_EXPORT_FILE_MAGIC, strlen(OUTPUT_EXPORT_FILE_MAGIC));
   const cryptonote::account_public_address &keys = get_account().get_keys().m_account_address;
   std::string header;
   header += std::string((const char *)&keys.m_spend_public_key, sizeof(crypto::public_key));
   header += std::string((const char *)&keys.m_view_public_key, sizeof(crypto::public_key));
+  PERF_TIMER(export_outputs_encryption);
   std::string ciphertext = encrypt_with_view_secret_key(header + oss.str());
   return magic + ciphertext;
 }
 //----------------------------------------------------------------------------------------------------
 size_t wallet2::import_outputs(const std::vector<tools::wallet2::transfer_details> &outputs)
 {
-  m_transfers.clear();
-  m_transfers.reserve(outputs.size());
+  PERF_TIMER(import_outputs);
+  const size_t original_size = m_transfers.size();
+  m_transfers.resize(outputs.size());
   for (size_t i = 0; i < outputs.size(); ++i)
   {
     transfer_details td = outputs[i];
 
+    // skip those we've already imported, or which have different data
+    if (i < original_size)
+    {
+      // compare the data used to create the key image below
+      const transfer_details &org_td = m_transfers[i];
+      if (!org_td.m_key_image_known)
+        goto process;
+#define CMPF(f) if (!(td.f == org_td.f)) goto process
+      CMPF(m_txid);
+      CMPF(m_key_image);
+      CMPF(m_internal_output_index);
+#undef CMPF
+      if (!(get_transaction_prefix_hash(td.m_tx) == get_transaction_prefix_hash(org_td.m_tx)))
+        goto process;
+
+      // copy anyway, since the comparison does not include ancillary fields which may have changed
+      m_transfers[i] = std::move(td);
+      continue;
+    }
+
+process:
+
     // the hot wallet wouldn't have known about key images (except if we already exported them)
     cryptonote::keypair in_ephemeral;
 
@@ -11011,9 +11067,9 @@ size_t wallet2::import_outputs(const std::vector<tools::wallet2::transfer_detail
     THROW_WALLET_EXCEPTION_IF(in_ephemeral.pub != out_key,
         error::wallet_internal_error, "key_image generated ephemeral public key not matched with output_key at index " + boost::lexical_cast<std::string>(i));
 
-    m_key_images[td.m_key_image] = m_transfers.size();
-    m_pub_keys[td.get_public_key()] = m_transfers.size();
-    m_transfers.push_back(std::move(td));
+    m_key_images[td.m_key_image] = i;
+    m_pub_keys[td.get_public_key()] = i;
+    m_transfers[i] = std::move(td);
   }
 
   return m_transfers.size();
@@ -11021,6 +11077,7 @@ size_t wallet2::import_outputs(const std::vector<tools::wallet2::transfer_detail
 //----------------------------------------------------------------------------------------------------
 size_t wallet2::import_outputs_from_str(const std::string &outputs_st)
 {
+  PERF_TIMER(import_outputs_from_str);
   std::string data = outputs_st;
   const size_t magiclen = strlen(OUTPUT_EXPORT_FILE_MAGIC);
   if (data.size() < magiclen || memcmp(data.data(), OUTPUT_EXPORT_FILE_MAGIC, magiclen))
@@ -11030,6 +11087,7 @@ size_t wallet2::import_outputs_from_str(const std::string &outputs_st)
 
   try
   {
+    PERF_TIMER(import_outputs_decrypt);
     data = decrypt_with_view_secret_key(std::string(data, magiclen));
   }
   catch (const std::exception &e)