--- a/Makefile~	2019-03-28 17:45:53.000000000 +0100
+++ b/Makefile	2019-06-02 10:36:55.587055453 +0200
@@ -21,7 +21,7 @@
 PNGQUANT = pngquant
 PNGQUANTFLAGS = --speed 1 --skip-if-larger --quality 85-95 --force
 BODY_DIMENSIONS = 136x128
-IMOPS := -size $(BODY_DIMENSIONS) canvas:none -compose copy -gravity center
+IMOPS = -size 136x128 -background none -gravity center -extent 136x128 -compose copy
 
 # zopflipng is better (about 5-10%) but much slower.  it will be used if
 # present.  pass ZOPFLIPNG= as an arg to make to use optipng instead.
@@ -165,13 +165,13 @@
 # imagemagick packaged with ubuntu trusty (6.7.7-10) by using -composite.
 
 $(EMOJI_DIR)/%.png: $(EMOJI_SRC_DIR)/%.png | $(EMOJI_DIR)
-	@convert $(IMOPS) "$<" -composite "PNG32:$@"
+	@gm convert $(IMOPS) "$<" "PNG32:$@"
 
 $(FLAGS_DIR)/%.png: $(FLAGS_SRC_DIR)/%.png ./waveflag | $(FLAGS_DIR)
 	@./waveflag $(FLAGS_DIR)/ "$<"
 
 $(RESIZED_FLAGS_DIR)/%.png: $(FLAGS_DIR)/%.png | $(RESIZED_FLAGS_DIR)
-	@convert $(IMOPS) "$<" -composite "PNG32:$@"
+	@gm convert $(IMOPS) "$<" "PNG32:$@"
 
 flag-symlinks: $(RESIZED_FLAG_FILES) | $(RENAMED_FLAGS_DIR)
 	@$(subst ^, ,                                  \