diff --git a/src/image.cpp b/src/image.cpp
index 68b569d..c8f9092 100644
--- a/src/image.cpp
+++ b/src/image.cpp
@@ -60,7 +60,7 @@ bool Image::load_file(std::string filename)
     return true;
 }
 
-bool Image::save_png(const std::string& path)
+bool Image::save_png(const std::string& path) const noexcept
 {
     bool ret = stbi_write_png(path.c_str(), width, height, comp, data(), 0);
     if (!ret)
@@ -68,7 +68,7 @@ bool Image::save_png(const std::string& path)
     return ret;
 }
 
-bool Image::save_jpg(const std::string& path, int quality)
+bool Image::save_jpg(const std::string& path, int quality) const noexcept
 {
     bool ret = stbi_write_jpg(path.c_str(), width, height, comp, data(), quality);
     if (!ret)
diff --git a/src/image.h b/src/image.h
index 03d4b7d..7cc3900 100644
--- a/src/image.h
+++ b/src/image.h
@@ -24,8 +24,8 @@ public:
     bool load_file(std::string filename);
     const uint8_t* data() const { return m_data.get(); }
     int size() const { return width * height * comp; }
-    bool save_png(const std::string& path);
-    bool save_jpg(const std::string& path, int quality);
+    bool save_png(const std::string& path) const noexcept;
+    bool save_jpg(const std::string& path, int quality) const noexcept;
     void create(int w, int h, uint8_t* data = nullptr)
     { 
         width = w; 
diff --git a/src/node_panel_brush.cpp b/src/node_panel_brush.cpp
index 9b8d208..ce132ea 100644
--- a/src/node_panel_brush.cpp
+++ b/src/node_panel_brush.cpp
@@ -686,6 +686,17 @@ void NodePanelBrushPreset::add_brush(std::shared_ptr<Brush> brush)
 
 bool NodePanelBrushPreset::export_ppbr(const std::string& path, const Image& header_image)
 {
+    std::regex r(R"((.*)[\\/]([^\\/]+)\.(\w+)$)");
+    std::smatch m;
+    if (!std::regex_search(path, m, r))
+        return false;
+    auto base = m[1].str();
+    auto name = m[2].str();
+    auto ext = m[3].str();
+    std::string out_path = base + "/" + name;
+
+    Asset::create_dir(out_path);
+    
     std::ofstream f(path, std::ios::binary);
     if (f.good())
     {
@@ -727,7 +738,10 @@ bool NodePanelBrushPreset::export_ppbr(const std::string& path, const Image& hea
 
         // header image
         if (has_header_image)
-            sw << header_image; 
+        {
+            sw << header_image;
+            header_image.save_jpg(out_path + "/header.jpg", 75);
+        }
 
         pb->increment();
 
@@ -735,6 +749,7 @@ bool NodePanelBrushPreset::export_ppbr(const std::string& path, const Image& hea
         sw.wu32((int)m_container->m_children.size());
         auto pr = std::make_unique<NodeStrokePreview>();
         pr->m_preview_size = pr->m_size = { 256, 128 };
+        int thumb_counter = 0;
         for (auto& c : m_container->m_children)
         {
             auto bpi = std::static_pointer_cast<NodeBrushPresetItem>(c);
@@ -743,6 +758,8 @@ bool NodePanelBrushPreset::export_ppbr(const std::string& path, const Image& hea
             Image img = pr->render_to_image();
             img.file_name = pr->m_brush->m_name;
             sw << img;
+            img.save_jpg(fmt::format(out_path + "/thumb-{:04d}.jpg", thumb_counter), 75);
+            thumb_counter++;
             pb->increment();
         }
 
@@ -966,16 +983,18 @@ bool NodePanelBrushPreset::import_abr(const std::string& path)
     });
 
     auto brushes = abr.compute_brushes(App::I->data_path);
-    for (const auto& b : brushes)
-    {
-        if (b->valid())
+    App::I->ui_task([&]{
+        for (const auto& b : brushes)
         {
-            LOG("add preset %s", b->m_name.c_str());
-            for (auto p : s_panels)
-                p->add_brush(b);
+            if (b->valid())
+            {
+                LOG("add preset %s", b->m_name.c_str());
+                for (auto p : s_panels)
+                    p->add_brush(b);
+            }
+            pb->increment();
         }
-        pb->increment();
-    }
+    });
 
     save();
     pb->destroy();
diff --git a/src/util.cpp b/src/util.cpp
index bdb944f..2a518cb 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -571,22 +571,28 @@ std::string unescape(const std::string& s)
 
 std::wstring str2wstr(const std::string& str)
 {
-    mbstate_t st = {};
-    std::wstring converted;
-    converted.resize(str.size());
-    const char* ptr = str.c_str();
-    std::mbsrtowcs((wchar_t*)converted.data(), &ptr, converted.capacity(), &st);
-    return converted;
+    //mbstate_t st = {};
+    //std::wstring converted;
+    //converted.resize(str.size());
+    //const char* ptr = str.c_str();
+    //std::mbsrtowcs((wchar_t*)converted.data(), &ptr, converted.capacity(), &st);
+    //return converted;
+    using convert_typeX = std::codecvt_utf8<wchar_t>;
+    std::wstring_convert<convert_typeX, wchar_t> converterX;
+    return converterX.from_bytes(str);
 }
 
 std::string wstr2str(const std::wstring & wstr)
 {
-    mbstate_t st = {};
-    std::string converted;
-    converted.resize(wstr.size());
-    const wchar_t * wptr = wstr.c_str();
-    std::wcsrtombs((char*)converted.data(), &wptr, converted.capacity(), &st);
-    return converted;
+    //mbstate_t st = {};
+    //std::string converted;
+    //converted.resize(wstr.size());
+    //const wchar_t * wptr = wstr.c_str();
+    //std::wcsrtombs((char*)converted.data(), &wptr, converted.capacity(), &st);
+    //return converted;
+    using convert_typeX = std::codecvt_utf8<wchar_t>;
+    std::wstring_convert<convert_typeX, wchar_t> converterX;
+    return converterX.to_bytes(wstr);
 }
 
 bool str_iequals(const std::string& a, const std::string& b)