cjpeg: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/cjpeg - from package: libjpeg-turbo

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/cjpeg - from package: libjpeg-turbo-progs

You may install the required package with command apt-get install {package}

Error in other languages:
cjpeg: bevel nie gevind nie
cjpeg: comandă negăsită
cjpeg: comando não encontrado
cjpeg: commande introuvable
cjpeg: command not found
cjpeg: käsku ei ole
cjpeg: không tìm thấy lệnh
cjpeg: komanda nerasta
cjpeg: Kommando nicht gefunden.
cjpeg: kommandot finns inte
cjpeg: komut yok
cjpeg: nie znaleziono polecenia
cjpeg: níor aimsíodh an t-ordú
cjpeg: no se encontró la orden
cjpeg: no s'ha trobat l'ordre
cjpeg: opdracht niet gevonden
cjpeg: parancs nem található
cjpeg: perintah tidak ditemukan
cjpeg: príkaz nenájdený
cjpeg: příkaz nenalezen
cjpeg: команда не найдена
cjpeg: командата не е открита
cjpeg: 命令找不到
cjpeg: コマンドが見つかりません