convert directory images to a new width

#!/bin/bash
#
# Parameters:
# <ARG> Width of the new images.
#
# Description:
# Resize all the images in the current directory to a new
# directory called <ARG>, using as new width the value of <ARG>.
#
# Usage:
# convert-img WIDTH

if [ -d $1 ];then
 echo -e "Correct usage:\n convert-img WIDTH";
else
 if [[ $1 =~ ^[0-9]+$ ]];then
 echo "Using width: $1";
 mkdir -p $1;
 for i in $(/bin/ls -1 | egrep -i "jpg|png|jpeg");do
 echo "Converting $i"
 convert -geometry $1 $i $1/$i;
 done
 else
 echo "Argument must be a number"
 fi
fi