diff --git a/Makefile b/Makefile
index 74434b5..b1899c2 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-PNGS = built/use_cases_diagram.png built/schema_diagram.png built/schema_graph.png
+PNGS = built/use_cases_diagram.png built/schema_diagram.png built/schema_graph.png built/screen_sequence_diagram.png
 PDFS = built/DesignUseCases.pdf built/screen_sequence_diagram.pdf 
 
 all: built/ $(PNGS) $(PDFS)
@@ -15,6 +15,10 @@ built/schema_graph.png:
 built/%.png: %.dot
 	dot -Tpng -o $@ $<
 
+
+built/screen_sequence_diagram.pdf: built/screen_sequence_diagram.png
+	convert built/screen_sequence_diagram.png built/screen_sequence_diagram.pdf
+
 built/%.pdf: %.tex
 	cd built/; pdflatex ../$<
 	cd built/; pdflatex ../$<