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