diff --git a/scripts/check-image-compatibility.sh b/scripts/check-image-compatibility.sh
index 6595a7225..1ee579b12 100644
--- a/scripts/check-image-compatibility.sh
+++ b/scripts/check-image-compatibility.sh
@@ -77,8 +77,6 @@ else
     working_dir=`readlink -m ${working_dir}`
 fi
 
-#get file extension and image type
-extension="${file_name##*.}"
 filename="${file_name%.*}"
 dest_file=${working_dir}/${filename}.raw
 image_type=$(qemu-img info ${file_abs_path} | grep 'file format:' | awk '{ print $3 }')