pdfimages: 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/pdfimages - from package: poppler-utils

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

On Debian possible default full paths are:

/usr/bin/pdfimages - from package: poppler-utils

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

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