wrjpgcom: 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/wrjpgcom - from package: libjpeg-turbo

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

On Debian possible default full paths are:

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

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

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