diff --git a/frontend/document/credocument.lua b/frontend/document/credocument.lua
index 39e2d1504..0c1df425d 100644
--- a/frontend/document/credocument.lua
+++ b/frontend/document/credocument.lua
@@ -3,11 +3,13 @@ local Document = require("document/document")
 local Configurable = require("configurable")
 local Blitbuffer = require("ffi/blitbuffer")
 local lfs = require("libs/libkoreader-lfs")
+local Image = require("ffi/mupdfimg")
 local Geom = require("ui/geometry")
 local Device = require("ui/device")
 local Screen = require("ui/screen")
 local Font = require("ui/font")
 local DEBUG = require("dbg")
+local ffi = require("ffi")
 
 local CreDocument = Document:new{
     -- this is defined in kpvcrlib/crengine/crengine/include/lvdocview.h
@@ -130,6 +132,16 @@ function CreDocument:getPageCount()
     return self._document:getPages()
 end
 
+function CreDocument:getCoverPageImage()
+    self._document:loadDocument(self.file)
+    local data, size = self._document:getCoverPageImageData()
+    if data and size then
+        local image = Image:fromData(data, size)
+        ffi.C.free(data)
+        return image
+    end
+end
+
 function CreDocument:getWordFromPosition(pos)
     local word_box = self._document:getWordFromPosition(pos.x, pos.y)
     DEBUG("CreDocument: get word box", word_box)
diff --git a/frontend/ui/otamanager.lua b/frontend/ui/otamanager.lua
index ac682f257..02a43243b 100644
--- a/frontend/ui/otamanager.lua
+++ b/frontend/ui/otamanager.lua
@@ -8,9 +8,9 @@ local _ = require("gettext")
 
 local OTAManager = {
     ota_servers = {
-        "http://vislab.bjmu.edu.cn/apps/koreader/ota/",
-        "http://koreader.ak-team.com/",
-        "http://hal9k.ifsc.usp.br/koreader/",
+        "http://vislab.bjmu.edu.cn:80/apps/koreader/ota/",
+        "http://koreader.ak-team.com:80/",
+        "http://hal9k.ifsc.usp.br:80/koreader/",
     },
     ota_channels = {
         "nightly",
diff --git a/frontend/ui/widget/imagewidget.lua b/frontend/ui/widget/imagewidget.lua
index c0c0420bf..fb10c3f6e 100644
--- a/frontend/ui/widget/imagewidget.lua
+++ b/frontend/ui/widget/imagewidget.lua
@@ -1,6 +1,26 @@
 local Widget = require("ui/widget/widget")
+local CacheItem = require("cacheitem")
 local Image = require("ffi/mupdfimg")
 local Geom = require("ui/geometry")
+local Cache = require("cache")
+local DEBUG = require("dbg")
+
+local ImageCache = Cache:new{
+    max_memsize = 2*1024*1024, -- 2M of image cache
+    current_memsize = 0,
+    cache = {},
+    -- this will hold the LRU order of the cache
+    cache_order = {}
+}
+
+local ImageCacheItem = CacheItem:new{}
+
+function ImageCacheItem:onFree()
+    if self.bb.free then
+        DEBUG("free image blitbuffer", self.bb)
+        self.bb:free()
+    end
+end
 
 --[[
 ImageWidget shows an image from a file
@@ -20,7 +40,21 @@ function ImageWidget:_render()
     local itype = string.lower(string.match(self.file, ".+%.([^.]+)") or "")
     if itype == "png" or itype == "jpg" or itype == "jpeg"
             or itype == "tiff" then
-        self._bb = Image:fromFile(self.file, self.width, self.height)
+        local hash = "image|"..self.file.."|"..(self.width or "").."|"..(self.height or "")
+        local cache = ImageCache:check(hash)
+        if cache then
+            -- hit cache
+            self._bb = cache.bb
+        else
+            -- cache this image
+            DEBUG("cache", hash)
+            local cache = ImageCacheItem:new{
+                bb = Image:fromFile(self.file, self.width, self.height),
+            }
+            cache.size = cache.bb.pitch * cache.bb.h
+            ImageCache:insert(hash, cache)
+            self._bb = cache.bb
+        end
     else
         error("Image file type not supported.")
     end
@@ -31,27 +65,24 @@ function ImageWidget:_render()
 end
 
 function ImageWidget:getSize()
-    if not self._bb then
-        self:_render()
-    end
+    self:_render()
     return Geom:new{ w = self._bb:getWidth(), h = self._bb:getHeight() }
 end
 
 function ImageWidget:rotate(degree)
-    if not self._bb then
-        self:_render()
-    end
+    self:_render()
     self._bb:rotate(degree)
 end
 
 function ImageWidget:paintTo(bb, x, y)
+    if self.hide then return end
+    -- self:_reader is called in getSize method
     local size = self:getSize()
     self.dimen = Geom:new{
         x = x, y = y,
         w = size.w,
         h = size.h
     }
-    if self.hide then return end
     bb:blitFrom(self._bb, x, y, 0, 0, size.w, size.h)
     if self.invert then
         bb:invertRect(x, y, size.w, size.h)
@@ -61,11 +92,4 @@ function ImageWidget:paintTo(bb, x, y)
     end
 end
 
-function ImageWidget:free()
-    if self._bb then
-        self._bb:free()
-        self._bb = nil
-    end
-end
-
 return ImageWidget
diff --git a/koreader-base b/koreader-base
index 1075c61f7..77654ebd3 160000
--- a/koreader-base
+++ b/koreader-base
@@ -1 +1 @@
-Subproject commit 1075c61f74888d0ab291c8a3d0ed55d9dde8457b
+Subproject commit 77654ebd378925518ff61186848d0d6d2ed9a501
diff --git a/spec/unit/document_spec.lua b/spec/unit/document_spec.lua
index b4cc77bf0..ca84cbeda 100644
--- a/spec/unit/document_spec.lua
+++ b/spec/unit/document_spec.lua
@@ -54,6 +54,12 @@ describe("EPUB document module", function()
         doc = DocumentRegistry:openDocument(sample_epub)
         assert.truthy(doc)
     end)
+    it("should get cover image", function()
+        local image = doc:getCoverPageImage()
+        assert.truthy(image)
+        assert.are.same(image:getWidth(), 442)
+        assert.are.same(image:getHeight(), 616)
+    end)
     it("should close document", function()
         doc:close()
     end)
diff --git a/test/leaves.epub b/test/leaves.epub
index afcf41e33..0060d0882 100644
Binary files a/test/leaves.epub and b/test/leaves.epub differ