diff --git a/tldr/convert b/tldr/convert
index ac72bdc5..6c856054 100644
--- a/tldr/convert
+++ b/tldr/convert
@@ -21,13 +21,13 @@ source: https://github.com/tldr-pages/tldr.git
 
 `convert {{path/to/input_image.png}} -resize 640x480 {{path/to/output_image.png}}`
 
-- Horizontally append images:
+- Scale an image to have a specified file size:
 
-`convert {{path/to/image1.png path/to/image2.png ...}} +append {{path/to/output_image.png}}`
+`convert {{path/to/input_image.png}} -define jpeg:extent=512kb {{path/to/output_image.jpg}}`
 
-- Vertically append images:
+- Vertically/Horizontally append images:
 
-`convert {{path/to/image1.png path/to/image2.png ...}} -append {{path/to/output_image.png}}`
+`convert {{path/to/image1.png path/to/image2.png ...}} {{-append|+append}} {{path/to/output_image.png}}`
 
 - Create a GIF from a series of images with 100ms delay between them:
 
diff --git a/tldr/linux/arecord b/tldr/linux/arecord
index b2ddd418..f940957e 100644
--- a/tldr/linux/arecord
+++ b/tldr/linux/arecord
@@ -27,3 +27,7 @@ source: https://github.com/tldr-pages/tldr.git
 - Allow interactive interface (e.g. use space-bar or enter to play or pause):
 
 `arecord --interactive`
+
+- Test your microphone by recording a 5 second sample and playing it back:
+
+`arecord -d 5 test-mic.wav && aplay test-mic.wav && rm test-mic.wav`