diff --git a/src/wi_stuff.cpp b/src/wi_stuff.cpp
index 58f8a349ae..0172223ec9 100644
--- a/src/wi_stuff.cpp
+++ b/src/wi_stuff.cpp
@@ -92,6 +92,7 @@ static const char *WI_Cmd[] = {
 	"Pic",
 
 	"NoAutostartMap",
+	"Screensize",
 
 	NULL
 };
@@ -169,7 +170,10 @@ private:
 	FGameTexture	*background = nullptr;
 	wbstartstruct_t *wbs;
 	level_info_t	*exitlevel;
-	
+	int			bgwidth = -1;
+	int			bgheight = -1;
+
+
 public:
 
 	DInterBackground(wbstartstruct_t *wbst);
@@ -456,6 +460,13 @@ bool DInterBackground::LoadBackground(bool isenterpic)
 					noautostartmap = true;
 					break;
 
+				case 15:	// screensize
+					sc.MustGetNumber();
+					bgwidth = sc.Number;
+					sc.MustGetNumber();
+					bgheight = sc.Number;
+					break;
+
 				readanimation:
 					sc.MustGetString();
 					an.LevelName = sc.String;
@@ -591,20 +602,23 @@ DEFINE_ACTION_FUNCTION(DInterBackground, updateAnimatedBack)
 void DInterBackground::drawBackground(int state, bool drawsplat, bool snl_pointeron)
 {
 	unsigned int i;
-	double animwidth = 320;		// For a flat fill or clear background scale animations to 320x200
-	double animheight = 200;
+	double animwidth = bgwidth;		// For a flat fill or clear background scale animations to 320x200
+	double animheight = bgheight;
 
 	if (background)
 	{
 		// background
 		if (background->isMiscPatch())
 		{
-			// scale all animations below to fit the size of the base pic
+			// if no explicit size was set scale all animations below to fit the size of the base pic
 			// The base pic is always scaled to fit the screen so this allows
 			// placing the animations precisely where they belong on the base pic
-			animwidth = background->GetDisplayWidth();
-			animheight = background->GetDisplayHeight();
-			if (animheight == 200) animwidth = 320;	// deal with widescreen replacements that keep the original coordinates.
+			if (bgwidth < 0 || bgheight < 0)
+			{
+				animwidth = background->GetDisplayWidth();
+				animheight = background->GetDisplayHeight();
+				if (animheight == 200) animwidth = 320;	// deal with widescreen replacements that keep the original coordinates.
+			}
 			DrawTexture(twod, background, 0, 0, DTA_FullscreenEx, FSMode_ScaleToFit43, TAG_DONE);
 		}
 		else
diff --git a/wadsrc/static/in_epi1.txt b/wadsrc/static/in_epi1.txt
index 3a20d009a7..627516ccaa 100644
--- a/wadsrc/static/in_epi1.txt
+++ b/wadsrc/static/in_epi1.txt
@@ -1,4 +1,5 @@
 Background wimap0
+Screensize 320 200
 Splat wisplat
 Pointer wiurh0 wiurh1
 
diff --git a/wadsrc/static/in_epi2.txt b/wadsrc/static/in_epi2.txt
index 340bb04223..c0f35568a4 100644
--- a/wadsrc/static/in_epi2.txt
+++ b/wadsrc/static/in_epi2.txt
@@ -1,4 +1,5 @@
 Background wimap1
+Screensize 320 200
 Splat wisplat
 Pointer wiurh0 wiurh1
 
diff --git a/wadsrc/static/in_epi3.txt b/wadsrc/static/in_epi3.txt
index 08e6fb341d..901a7655ca 100644
--- a/wadsrc/static/in_epi3.txt
+++ b/wadsrc/static/in_epi3.txt
@@ -1,4 +1,5 @@
 Background wimap2
+Screensize 320 200
 Splat wisplat
 Pointer wiurh0 wiurh1
 
diff --git a/wadsrc/static/in_htc1.txt b/wadsrc/static/in_htc1.txt
index 15c2ac6015..20902bdfd6 100644
--- a/wadsrc/static/in_htc1.txt
+++ b/wadsrc/static/in_htc1.txt
@@ -1,5 +1,6 @@
 NoAutostartMap
 Background mape1
+Screensize 320 200
 Splat in_x
 Pointer in_yah
 
diff --git a/wadsrc/static/in_htc2.txt b/wadsrc/static/in_htc2.txt
index 9d506d777c..e123a26e29 100644
--- a/wadsrc/static/in_htc2.txt
+++ b/wadsrc/static/in_htc2.txt
@@ -1,5 +1,6 @@
 NoAutostartMap
 Background mape2
+Screensize 320 200
 Splat in_x
 Pointer in_yah
 
diff --git a/wadsrc/static/in_htc3.txt b/wadsrc/static/in_htc3.txt
index 545c59d3e0..21dd15c99e 100644
--- a/wadsrc/static/in_htc3.txt
+++ b/wadsrc/static/in_htc3.txt
@@ -1,5 +1,6 @@
 NoAutostartMap
 Background mape3
+Screensize 320 200
 Splat in_x
 Pointer in_yah