diff --git a/configure.ac b/configure.ac
index 9d8888a..4463a8c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -379,6 +379,16 @@ AM_CONDITIONAL(BUILD_ID3_LOADER, test "$id3_ok" = yes)
 
 AM_CONDITIONAL(BUILD_TEST, false)
 
+AC_ARG_ENABLE([debug],
+  [AS_HELP_STRING([--enable-debug], [Enable debug features @<:@default=no@:>@])],
+  [
+    if test x$enableval = xyes; then
+      AC_DEFINE(IMLIB2_DEBUG, 1, [Enable debug features])
+    fi
+  ]
+)
+AM_CONDITIONAL(BUILD_DEBUG, test "$enable_debug" = "yes")
+
 EC_C_WARNINGS()
 EC_C_VISIBILITY(yes)
 EC_C_ASAN()
diff --git a/src/lib/Makefile.am b/src/lib/Makefile.am
index bfff8e1..340249e 100644
--- a/src/lib/Makefile.am
+++ b/src/lib/Makefile.am
@@ -25,6 +25,8 @@ colormod.h \
 common.h \
 context.c \
 context.h \
+debug.c \
+debug.h \
 draw.c \
 draw.h \
 dynamic_filters.c \
@@ -91,6 +93,9 @@ MY_LIBS = $(FREETYPE_LIBS) $(DLOPEN_LIBS) -lm
 if BUILD_X11
 MY_LIBS += -lXext -lX11 @X_SHM_FD_LIBS@
 endif
+if BUILD_DEBUG
+MY_LIBS += $(CLOCK_LIBS)
+endif
 
 if BUILD_MMX
 libImlib2_la_LIBADD       = $(MMX_OBJS) $(MY_LIBS)
diff --git a/src/lib/common.h b/src/lib/common.h
index 0df2338..3b5ec76 100644
--- a/src/lib/common.h
+++ b/src/lib/common.h
@@ -10,6 +10,14 @@
 #include <math.h>
 #include <time.h>
 
+#if __GNUC__
+#define __PRINTF_N__(no)  __attribute__((__format__(__printf__, (no), (no)+1)))
+#else
+#define __PRINTF_N__(no)
+#endif
+#define __PRINTF__   __PRINTF_N__(1)
+#define __PRINTF_2__ __PRINTF_N__(2)
+
 #define DATABIG unsigned long long
 #define DATA64  unsigned long long
 #define DATA32  unsigned int
diff --git a/src/lib/debug.c b/src/lib/debug.c
new file mode 100644
index 0000000..e842249
--- /dev/null
+++ b/src/lib/debug.c
@@ -0,0 +1,71 @@
+#include "common.h"
+#include <stdarg.h>
+
+#include "debug.h"
+
+#if IMLIB2_DEBUG
+
+unsigned int        __imlib_debug = 0;
+
+static FILE        *opt_fout = NULL;
+
+__attribute__((constructor))
+     static void         _debug_init(void)
+{
+   const char         *s;
+   int                 p1, p2;
+
+   opt_fout = stdout;
+
+   s = getenv("IMLIB2_DEBUG");
+   if (!s)
+      return;
+
+   sscanf(s, "%d:%d", &p1, &p2);
+
+   __imlib_debug = p1;
+   opt_fout = (p2) ? stderr : stdout;
+}
+
+#if USE_MONOTONIC_CLOCK
+#include <time.h>
+#else
+#include <sys/time.h>
+#endif
+
+unsigned int
+__imlib_time_us(void)
+{
+#if USE_MONOTONIC_CLOCK
+   struct timespec     ts;
+
+   clock_gettime(CLOCK_MONOTONIC, &ts);
+
+   return (unsigned int)(ts.tv_sec * 1000000 + ts.tv_nsec / 1000);
+#else
+   struct timeval      timev;
+
+   gettimeofday(&timev, NULL);
+
+   return (unsigned int)(timev.tv_sec * 1000000 + timev.tv_usec);
+#endif
+}
+
+void
+__imlib_printf(const char *pfx, const char *fmt, ...)
+{
+   char                fmtx[1024];
+   va_list             args;
+
+   va_start(args, fmt);
+
+   if (pfx)
+     {
+        snprintf(fmtx, sizeof(fmtx), "%-4s: %s", pfx, fmt);
+        fmt = fmtx;
+     }
+   vfprintf(opt_fout, fmt, args);
+   va_end(args);
+}
+
+#endif /* IMLIB2_DEBUG */
diff --git a/src/lib/debug.h b/src/lib/debug.h
new file mode 100644
index 0000000..f6bab08
--- /dev/null
+++ b/src/lib/debug.h
@@ -0,0 +1,32 @@
+#ifndef IMLIB2_DEDUG_H
+#define IMLIB2_DEDUG_H
+
+#if IMLIB2_DEBUG
+
+#define D(fmt...)     if (__imlib_debug)     __imlib_printf(DBG_PFX, fmt)
+#define DC(M, fmt...) if (__imlib_debug & M) __imlib_printf(DBG_PFX, fmt)
+
+#define DBG_FILE	0x0001
+#define DBG_LOAD	0x0002
+#define DBG_LDR 	0x0004
+
+#if __LOADER_COMMON_H
+#undef D
+#define D(fmt...) DC(DBG_LDR, fmt)
+#endif
+
+__EXPORT__ extern unsigned int __imlib_debug;
+
+__EXPORT__ __PRINTF_2__ void __imlib_printf(const char *pfx,
+                                            const char *fmt, ...);
+
+unsigned int        __imlib_time_us(void);
+
+#else
+
+#define D(fmt...)
+#define DC(fmt...)
+
+#endif /* IMLIB2_DEBUG */
+
+#endif /* IMLIB2_DEDUG_H */
diff --git a/src/modules/loaders/loader_bmp.c b/src/modules/loaders/loader_bmp.c
index 62a501e..484b5c4 100644
--- a/src/modules/loaders/loader_bmp.c
+++ b/src/modules/loaders/loader_bmp.c
@@ -10,12 +10,7 @@
 #include "loader_common.h"
 #include <sys/stat.h>
 
-#define DEBUG 0
-#if DEBUG
-#define D(fmt...) fprintf(stdout, "BMP loader: " fmt)
-#else
-#define D(fmt...)
-#endif
+#define DBG_PFX "LDR-bmp"
 #define Dx(fmt...)
 
 /* The BITMAPFILEHEADER (size 14) */
diff --git a/src/modules/loaders/loader_common.h b/src/modules/loaders/loader_common.h
index d1716c9..512ade8 100644
--- a/src/modules/loaders/loader_common.h
+++ b/src/modules/loaders/loader_common.h
@@ -3,6 +3,7 @@
 
 #include "config.h"
 #include "common.h"
+#include "debug.h"
 #include "image.h"
 
 __EXPORT__ char     load(ImlibImage * im, ImlibProgressFunction progress,
diff --git a/src/modules/loaders/loader_ico.c b/src/modules/loaders/loader_ico.c
index fc69192..0aa739f 100644
--- a/src/modules/loaders/loader_ico.c
+++ b/src/modules/loaders/loader_ico.c
@@ -8,12 +8,7 @@
 #include "loader_common.h"
 #include <limits.h>
 
-#define DEBUG 0
-#if DEBUG
-#define D(fmt...) fprintf(stdout, "ICO loader: " fmt)
-#else
-#define D(fmt...)
-#endif
+#define DBG_PFX "LDR-ico"
 
 /* The ICONDIR */
 typedef struct {
diff --git a/src/modules/loaders/loader_jpeg.c b/src/modules/loaders/loader_jpeg.c
index 1c9501a..831d6ca 100644
--- a/src/modules/loaders/loader_jpeg.c
+++ b/src/modules/loaders/loader_jpeg.c
@@ -3,12 +3,7 @@
 #include <setjmp.h>
 #include "exif.h"
 
-#define DEBUG 0
-#if DEBUG
-#define D(fmt...) fprintf(stdout, "JPEG loader: " fmt)
-#else
-#define D(fmt...)
-#endif
+#define DBG_PFX "LDR-jpg"
 
 typedef struct {
    struct jpeg_error_mgr jem;
diff --git a/src/modules/loaders/loader_xbm.c b/src/modules/loaders/loader_xbm.c
index e7c648a..af8b21c 100644
--- a/src/modules/loaders/loader_xbm.c
+++ b/src/modules/loaders/loader_xbm.c
@@ -3,12 +3,7 @@
  */
 #include "loader_common.h"
 
-#define DEBUG 0
-#if DEBUG
-#define D(fmt...) fprintf(stdout, "XBM loader: " fmt)
-#else
-#define D(fmt...)
-#endif
+#define DBG_PFX "LDR-xbm"
 
 static const DATA32 _bitmap_colors[2] = { 0xffffffff, 0xff000000 };