diff --git a/scripts/thumbnail.sh b/scripts/thumbnail.sh
index 8dbf7be..318c927 100755
--- a/scripts/thumbnail.sh
+++ b/scripts/thumbnail.sh
@@ -1,4 +1,8 @@
 #!/bin/bash
+if ! [ -x "$(command -v convert)" ]; then
+  echo 'Error: ImageMagick is not installed. Please install ImageMagick and try again.'
+  exit 1
+fi
 for i in *.jpg; do
     convert "$i" -thumbnail 400 "thumbs/$i";
 done;