diff --git a/server/control_session_http.cpp b/server/control_session_http.cpp
index 1d7ba5bd..080f26e1 100644
--- a/server/control_session_http.cpp
+++ b/server/control_session_http.cpp
@@ -24,6 +24,7 @@
 #include "common/aixlog.hpp"
 #include "common/utils/file_utils.hpp"
 #include "control_session_ws.hpp"
+#include "image_cache.hpp"
 #include "stream_session_ws.hpp"
 
 // 3rd party headers
@@ -288,7 +289,7 @@ void ControlSessionHttp::handle_request(http::request<Body, http::basic_fields<A
     {
         pos += image_cache_target.size();
         target = target.substr(pos);
-        auto image = settings_.http.image_cache.getImage(std::string(target));
+        auto image = ImageCache::instance().getImage(std::string(target));
         LOG(DEBUG, LOG_TAG) << "image cache: " << target << ", found: " << image.has_value() << "\n";
         if (image.has_value())
         {
diff --git a/server/image_cache.hpp b/server/image_cache.hpp
index 06a576b0..785b3116 100644
--- a/server/image_cache.hpp
+++ b/server/image_cache.hpp
@@ -30,12 +30,19 @@
 #include <string>
 
 
+/// Image cache, used to store current album art per stream
 class ImageCache
 {
 public:
-    ImageCache() = default;
-    virtual ~ImageCache() = default;
+    /// @return singleton to the image cache
+    static ImageCache& instance()
+    {
+        static ImageCache instance_;
+        return instance_;
+    }
 
+    /// Store the base64 encoded @p image for @p key (the session that stores the image) in the cache
+    /// @return url of the cached image (md5 of key + image data) appended with @p extension
     std::string setImage(const std::string& key, std::string image, const std::string& extension)
     {
         if (image.empty())
@@ -51,7 +58,7 @@ public:
         hash.process_bytes(image.data(), image.size());
         hash.get_digest(digest);
         std::string filename;
-        const auto intDigest = reinterpret_cast<const int*>(&digest);
+        const auto* intDigest = reinterpret_cast<const int*>(&digest);
         boost::algorithm::hex_lower(intDigest, intDigest + (sizeof(md5::digest_type) / sizeof(int)), std::back_inserter(filename));
         auto ext = extension;
         if (ext.find('.') == 0)
@@ -63,6 +70,7 @@ public:
         return filename;
     };
 
+    /// Clear image for @p key (the stream session's name)
     void clear(const std::string& key)
     {
         std::lock_guard<std::mutex> lock(mutex_);
@@ -77,6 +85,7 @@ public:
         }
     }
 
+    /// @return base64 encoded image for url (the one returned by "setImage")
     std::optional<std::string> getImage(const std::string& url)
     {
         std::lock_guard<std::mutex> lock(mutex_);
@@ -88,6 +97,9 @@ public:
     }
 
 private:
+    ImageCache() = default;
+    ~ImageCache() = default;
+
     std::map<std::string, std::string> key_to_url_;
     std::map<std::string, std::string> url_to_data_;
     std::mutex mutex_;
diff --git a/server/server_settings.hpp b/server/server_settings.hpp
index 33d88ade..66f458fa 100644
--- a/server/server_settings.hpp
+++ b/server/server_settings.hpp
@@ -21,7 +21,6 @@
 
 // local headers
 #include "common/utils/string_utils.hpp"
-#include "image_cache.hpp"
 
 // standard headers
 #include <string>
@@ -73,7 +72,6 @@ struct ServerSettings
         std::vector<std::string> ssl_bind_to_address{{"0.0.0.0"}};
         std::string doc_root{""};
         std::string host{"<hostname>"};
-        inline static ImageCache image_cache;
     };
 
     struct Tcp
diff --git a/server/streamreader/jack_stream.cpp b/server/streamreader/jack_stream.cpp
index 8fb76d0d..549625f7 100644
--- a/server/streamreader/jack_stream.cpp
+++ b/server/streamreader/jack_stream.cpp
@@ -20,8 +20,6 @@
 // prototype/interface header file
 #include "jack_stream.hpp"
 
-#include <jack/jack.h>
-
 // local headers
 #include "common/aixlog.hpp"
 #include "common/snap_exception.hpp"
@@ -59,7 +57,6 @@ void float_to_s24(char* dst, jack_default_audio_sample_t* src, unsigned long nsa
 
     while (nsamples--)
     {
-
         // float to S24 conversion
         if (*src <= -1.0f)
         {
diff --git a/server/streamreader/jack_stream.hpp b/server/streamreader/jack_stream.hpp
index dad1cf7b..bbb451e9 100644
--- a/server/streamreader/jack_stream.hpp
+++ b/server/streamreader/jack_stream.hpp
@@ -22,7 +22,6 @@
 
 // local headers
 #include "pcm_stream.hpp"
-#include <server/server_settings.hpp>
 
 // 3rd party headers
 #include <boost/asio/io_context.hpp>
diff --git a/server/streamreader/pcm_stream.cpp b/server/streamreader/pcm_stream.cpp
index cd846cad..bb2169aa 100644
--- a/server/streamreader/pcm_stream.cpp
+++ b/server/streamreader/pcm_stream.cpp
@@ -28,6 +28,7 @@
 #include "common/utils/string_utils.hpp"
 #include "control_error.hpp"
 #include "encoder/encoder_factory.hpp"
+#include "image_cache.hpp"
 
 // 3rd party headers
 #include <boost/asio/ip/host_name.hpp>
@@ -537,7 +538,7 @@ void PcmStream::setProperties(const Properties& properties)
     if (props.metadata.has_value() && props.metadata->art_data.has_value() && !props.metadata->art_url.has_value())
     {
         auto data = base64_decode(props.metadata->art_data->data);
-        auto md5 = ServerSettings::Http::image_cache.setImage(getName(), std::move(data), props.metadata->art_data->extension);
+        auto md5 = ImageCache::instance().setImage(getName(), std::move(data), props.metadata->art_data->extension);
 
         std::stringstream url;
         url << "http://" << server_settings_.http.host << ":" << server_settings_.http.port << "/__image_cache?name=" << md5;
@@ -545,7 +546,7 @@ void PcmStream::setProperties(const Properties& properties)
     }
     else if (!props.metadata.has_value() || !props.metadata->art_data.has_value())
     {
-        ServerSettings::Http::image_cache.clear(getName());
+        ImageCache::instance().clear(getName());
     }
 
     if (props == properties_)