diff --git a/render/rendertest.py b/render/rendertest.py
index 38e96eb..af1d5a6 100755
--- a/render/rendertest.py
+++ b/render/rendertest.py
@@ -11,10 +11,17 @@ import subprocess
 
 ROOT = os.path.dirname(os.path.abspath(__file__))
 imagecompare = f'{ROOT}/imagecompare'
-magick = f'magick' # set path for imagemagick if need
 WORKDIR = f'{ROOT}/work'
 REPORT_ROOT = f'{ROOT}' # FIXME should be workdir?
 
+def get_imagemagick_convert_cmd() -> str:
+    if shutil.which("magick"):
+        return "magick"
+    if shutil.which("convert"):
+        return "convert"
+    raise RuntimeError("No ImageMagick binary found (tried: magick, convert)")
+convert = get_imagemagick_convert_cmd()
+
 # TODO rename to <map>_<description>_<issue(opt)>
 saves = []
 for (_, _, files) in os.walk(os.path.join(ROOT, 'save')):
@@ -184,6 +191,7 @@ def command_png():
 	new_gold_base = f'{WORKDIR}/gold'
 	mkdir_p(new_gold_base)
 	with concurrent.futures.ThreadPoolExecutor() as executor:
+		futures = []
 		for test in args.tests:
 			for channel, _ in channels.items():
 				image_base = f'{test}_{channel}'
@@ -191,7 +199,10 @@ def command_png():
 				image_new_gold = f'{new_gold_base}/{image_base}.png'
 
 				# TODO if verbose: print(f'convert to {image_new_gold}')
-				executor.submit(subprocess.run, [magick, image_test, '-auto-orient', image_new_gold], check=True)
+				future = executor.submit(subprocess.run, [convert, image_test, '-auto-orient', image_new_gold], check=True)
+				futures.append(future)
+		for f in concurrent.futures.as_completed(futures):
+			f.result()
 
 def command_run():
 	compile()