pilconvert: 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/pilconvert - from package: python3-pil

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

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