send_image: 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 Debian possible default full paths are:

/usr/bin/send_image - from package: ctn

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

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