src/image.cpp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/image.cpp b/src/image.cpp
index fef85af7e4..67c0c32568 100644
--- a/src/image.cpp
+++ b/src/image.cpp
@@ -41,6 +41,7 @@
 #include <boost/algorithm/string.hpp>
 #include <boost/functional/hash_fwd.hpp>

+#include <mutex>
 #include <set>

 static lg::log_domain log_display("display");
@@ -105,23 +106,30 @@ class cache_type
 public:
    cache_type()
        : content_()
+       , cache_lock_()
    {
    }

    cache_item<T>& get_element(int index)
    {
-       if(static_cast<unsigned>(index) >= content_.size())
+       std::lock_guard<std::mutex> lock(cache_lock_);
+
+       if(static_cast<unsigned>(index) >= content_.size()) {
            content_.resize(index + 1);
+       }
+
        return content_[index];
    }

    void flush()
    {
+       std::lock_guard<std::mutex> lock(cache_lock_);
        content_.clear();
    }

 private:
    std::vector<cache_item<T>> content_;
+   std::mutex cache_lock_;
 };

 template<typename T>