Allow to zoom in further when using the -t flag.
The default is tiny on resolutions higher than FullHD.

Index: config.def.h
--- config.def.h.orig
+++ config.def.h
@@ -65,10 +65,10 @@ static const int CACHE_SIZE_FALLBACK = 32 * 1024 * 102
 #ifdef _THUMBS_CONFIG
 
 /* thumbnail sizes in pixels (width == height): */
-static const int thumb_sizes[] = { 32, 64, 96, 128, 160 };
+static const int thumb_sizes[] = { 160, 240, 320, 460, 640 };
 
 /* thumbnail size at startup, index into thumb_sizes[]: */
-static const int THUMB_SIZE = 3;
+static const int THUMB_SIZE = 4;
 
 #endif
 #ifdef _MAPPINGS_CONFIG
@@ -86,7 +86,7 @@ static const keymap_t keys[] = {
 	{ 0,            XK_Return,        g_switch_mode,        None },
 	{ 0,            XK_f,             g_toggle_fullscreen,  None },
 	{ 0,            XK_b,             g_toggle_bar,         None },
-	{ ControlMask,  XK_x,             g_prefix_external,    None },
+	{ 0,            XK_x,             g_prefix_external,    None },
 	{ 0,            XK_g,             g_first,              None },
 	{ 0,            XK_G,             g_n_or_last,          None },
 	{ 0,            XK_r,             g_reload_image,       None },