vips-7.40: command not found

Have You tried accessing the binary with the full path?

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/vips-7.40 - from package: libvips-tools

You may install the required package with command apt-get install {package}
Error in other languages:
vips-7.40: bevel nie gevind nie
vips-7.40: comandă negăsită
vips-7.40: comando não encontrado
vips-7.40: commande introuvable
vips-7.40: command not found
vips-7.40: käsku ei ole
vips-7.40: không tìm thấy lệnh
vips-7.40: komanda nerasta
vips-7.40: Kommando nicht gefunden.
vips-7.40: kommandot finns inte
vips-7.40: komut yok
vips-7.40: nie znaleziono polecenia
vips-7.40: níor aimsíodh an t-ordú
vips-7.40: no se encontró la orden
vips-7.40: no s'ha trobat l'ordre
vips-7.40: opdracht niet gevonden
vips-7.40: parancs nem található
vips-7.40: perintah tidak ditemukan
vips-7.40: príkaz nenájdený
vips-7.40: příkaz nenalezen
vips-7.40: команда не найдена
vips-7.40: командата не е открита
vips-7.40: 命令找不到
vips-7.40: コマンドが見つかりません