universal convert shell script, name it as a destination extension, eg. 'jpg'

convert

#!/bin/bash -e
src="${1?:No filename specified}"
dst="${src%.*}.$(basename ${0})"
echo "Converting '${src}' to '${dst}'"
[ -f "${src}" ] || { echo "Source file '${src}' not found"; exit 1; }
some_command "${src}" "${dst}"
[ -f "${dst}" ] || { echo "Destination file '${dst}' not found"; exit 1; }
rm -f "${src}"