diff --git a/pysitemap/base_crawler.py b/pysitemap/base_crawler.py
index 37867ac..2b669c8 100644
--- a/pysitemap/base_crawler.py
+++ b/pysitemap/base_crawler.py
@@ -14,8 +14,8 @@ class Crawler:
         'txt': TextWriter
     }
 
-    def __init__(self, rooturl, out_file, out_format='xml', maxtasks=100, exclude_urls=[], exclude_imgs=[],
-                 verifyssl=True, headers=None, timezone_offset=0, changefreq=None, priorities=None,
+    def __init__(self, rooturl, out_file, out_format='xml', maxtasks=10, exclude_urls=list, exclude_imgs=list,
+                 image_root_urls=list, verifyssl=True, headers=None, timezone_offset=0, changefreq=None, priorities=None,
                  todo_queue_backend=set, done_backend=dict, done_images=list):
         """
         Crawler constructor
@@ -25,12 +25,14 @@ class Crawler:
         :type out_file: str
         :param out_format: sitemap type [xml | txt]. Default xml
         :type out_format: str
-        :param maxtasks: maximum count of tasks. Default 100
+        :param maxtasks: maximum count of tasks. Default 10
         :type maxtasks: int
         :param exclude_urls: excludable url paths relative to root url
         :type exclude_urls: list
         :param exclude_imgs: excludable img url paths relative to root url
         :type exclude_imgs: list
+        :param image_root_urls: recognized image root urls on the domain
+        :type image_root_urls: list
         :param verifyssl: verify website certificate?
         :type verifyssl: boolean
         :param timezone_offset: timezone offset for lastmod tags
@@ -43,6 +45,7 @@ class Crawler:
         self.rooturl = rooturl
         self.exclude_urls = exclude_urls
         self.exclude_imgs = exclude_imgs
+        self.image_root_urls = image_root_urls
         self.todo_queue = todo_queue_backend()
         self.busy = set()
         self.done = done_backend()
@@ -127,6 +130,10 @@ class Crawler:
         """
         Check url resource mimetype
         """
+
+        self.todo_queue.remove(url)
+        self.busy.add(url)
+
         try:
             resp = await self.session.get(url)
         except Exception as exc:
@@ -135,10 +142,14 @@ class Crawler:
             mime = resp.headers.get('content-type')
             if (resp.status == 200 and
                 bool(re.search(re.compile(r"{}".format(expected)), mime))):
+                resp.close()
+                self.busy.remove(url)
                 return True
+        resp.close()
+        self.busy.remove(url)
         return False
 
-    async def addimages(self, data):
+    async def addimages(self, data, url):
         """
         Find all images in website data
         """
@@ -161,15 +172,41 @@ class Crawler:
         imgs = re.findall(r'(?i)src=["\']?([^\s\"\'<>]+)', str(lines_tmp))
 
         for img in imgs:
+            image_url = ""
             if not await self.contains(img, self.exclude_imgs, rlist=True):
+
                 if img.startswith(self.rooturl):
-                      if (await self.mimechecker(img, '^image\/') and
-                          img not in self.done_images):
-                          imgs_ok.append(img)
+                    image_url = img
+
                 elif not img.startswith("http"):
-                      if (await self.mimechecker(img, '^image\/') and
-                          img not in self.done_images):
-                          imgs_ok.append(re.sub('/$', '', self.rooturl) + img)
+                    for image_root_url in self.image_root_urls:
+                        if url.startswith(image_root_url):
+                            image_url = image_root_url + img
+                            break
+
+                if (image_url != "" and
+                    image_url not in self.done_images and
+                    image_url not in self.busy and
+                    image_url not in self.todo_queue):
+                    self.todo_queue.add(image_url)
+                    # Acquire semaphore
+                    await self.sem.acquire()
+                    # Create async task
+                    task = asyncio.ensure_future(self.mimechecker(image_url, '^image\/'))
+                    # Add collback into task to release semaphore
+                    task.add_done_callback(lambda t: self.sem.release())
+                    # Callback to remove task from tasks
+                    task.add_done_callback(self.tasks.remove)
+                    # Add task into tasks
+                    self.tasks.add(task)
+                    try:
+                        result = await asyncio.wait_for(task, timeout=20)
+                        if (result):
+                            imgs_ok.append(image_url)
+                    except asyncio.TimeoutError:
+                        print("couldn't add image:", image_url)
+                        task.cancel()
+                        pass
 
         self.done_images.extend(imgs_ok)
         return imgs_ok
@@ -204,7 +241,7 @@ class Crawler:
                 data = (await resp.read()).decode('utf-8', 'replace')
                 urls = re.findall(r'(?i)href=["\']?([^\s"\'<>]+)', data)
                 lastmod = resp.headers.get('last-modified')
-                imgs = await self.addimages(data)
+                imgs = await self.addimages(data, url)
                 asyncio.Task(self.addurls([(u, url) for u in urls]))
 
                 try: pr = await self.urldict(url, self.changefreq)