diff --git a/make-includes/standard_rules.make b/make-includes/standard_rules.make
index 586c2b2..55dc3f4 100755
--- a/make-includes/standard_rules.make
+++ b/make-includes/standard_rules.make
@@ -88,12 +88,31 @@
 	$(call xslt,$<,xml2html.xsl,$(call xslt_parameter,subject-code,'$(SUBJECT_CODE)'),$(call xslt_parameter,paper-number,'$(PAPER_NUMBER)'),$(call xslt_parameter,paper-year,'$(PAPER_YEAR)'),$(call xslt_parameter,paper-period,'$(PAPER_PERIOD)')) > $@
 endif
 #
-# PNG from TIFF (normal)
+# Image rules can be a bit messy, because the prerequisite might be in any one
+# of several different formats, but we want to apply the same commands anyway
+# (e.g., ImageMagick convert) to generate the target. It would be nice if we
+# could specify variable file types in a prerequisite of a pattern rule (e.g.,
+# %-foo.png: %.png %.jpg %.tif), but unfortunately we can't :(. The solution is
+# to create a make function to refactor the commands, and then specify as many
+# rules as required depending on the number of file formats. We still end up
+# repeating the rule actions, but at least the guts of the action is coded only
+# once in the function.
 #
+# PNG from TIFF, JPEG, PICT (normal image)
+# Note: The second rule omits the %.png target to avoid a circular dependency.
+#
+convert_normal = `$(CONVERT) "$(1)" "$(2)"`
+
 %.png %-print.png %-web.png: %.tif
-	$(CONVERT) "$<" $(IMGDIR)/$@
+	$(call convert-normal,$<,$(IMGDIR)/$@)
+
+%.png %-print.png %-web.png: %.jpg
+	$(call convert-normal,$<,$(IMGDIR)/$@)
+
+%.png %-print.png %-web.png: %.pict
+	$(call convert-normal,$<,$(IMGDIR)/$@)
 #
-# PNG from TIFF (slide background)
+# PNG from PNG, TIFF, JPEG, PICT (slide background)
 #
 # We lighten these so that they don't overwhelm the text. Note that 15% is
 # too light for most data projectors, so let's try 33% and see what
@@ -102,18 +121,35 @@
 #
 # Includes both blurred and unblurred versions, use as required.
 #
-%-BG.png: $(IMGDIR)/%.tif
-	$(CONVERT) $< -threshold "-1" -depth 16 - | $(COMPOSITE) -dissolve 33% $< - $(IMGDIR)/$@
+# Unblurred:
+convert_bg = `$(CONVERT) "$(1)" -threshold "-1" -depth 16 - | $(COMPOSITE) -dissolve 33% "$(1)" - "$(2)"`
+
+%-BG.png: %.tif
+	$(call convert_bg,$<,$(IMGDIR)/$@)
+
+%-BG.png: %.png
+	$(call convert_bg,$<,$(IMGDIR)/$@)
+
+%-BG.png: %.jpg
+	$(call convert_bg,$<,$(IMGDIR)/$@)
+
+%-BG.png: %.pict
+	$(call convert_bg,$<,$(IMGDIR)/$@)
 #
+# Blurred:
+convert_bg_blur = `$(CONVERT) -blur 0.5 "$(1)" "$(2)"; $(CONVERT) "$(2)" -threshold "-1" -depth 16 - | $(COMPOSITE) -dissolve 33% "$(2)" - "$(3)"; rm -f "$(2)"`
+
 %-BG-blur.png: %.tif
-	$(CONVERT) -blur 0.5 $< $(IMGDIR)/$*.png
-	$(CONVERT) $(IMGDIR)/$*.png -threshold "-1" -depth 16 - | $(COMPOSITE) -dissolve 33% $(IMGDIR)/$*.png - $(IMGDIR)/$@
-	@rm -f $(IMGDIR)/$*.png
-#
-# PNG from PICT.
-#
-%.png %-print.png %-web.png: %.pict
-	$(CONVERT) "$<" $(IMGDIR)/$@
+	$(call convert_bg_blur,$<,$(IMGDIR)/$*-tmp.png,$(IMGDIR)/$@)
+
+%-BG-blur.png: %.png
+	$(call convert_bg_blur,$<,$(IMGDIR)/$*-tmp.png,$(IMGDIR)/$@)
+
+%-BG-blur.png: %.jpg
+	$(call convert_bg_blur,$<,$(IMGDIR)/$*-tmp.png,$(IMGDIR)/$@)
+
+%-BG-blur.png: %.pict
+	$(call convert_bg_blur,$<,$(IMGDIR)/$*-tmp.png,$(IMGDIR)/$@)
 #
 # PNG from XCF.
 #
@@ -194,6 +230,12 @@
 %-web-zoom.png: %.svg
 	$(INKSCAPE) --file=$< --without-gui --export-area-drawing --export-background-opacity=1.0 --export-dpi=144 --export-png=$(IMGDIR)/$@
 
+%-print-zoom.png: %.svg
+	$(INKSCAPE) --file=$< --without-gui --export-area-drawing --export-background-opacity=1.0 --export-dpi=300 --export-png=$(IMGDIR)/$@
+
+%-print-zoom-transparent.png: %.svg
+	$(INKSCAPE) --file=$< --without-gui --export-area-drawing --export-background-opacity=0 --export-dpi=300 --export-png=$(IMGDIR)/$@
+
 %-transparent.png: %.svg
 	$(INKSCAPE) --file=$< --without-gui --export-area-drawing --export-background-opacity=0 --export-dpi=96 --export-png=$(IMGDIR)/$@
 #