psimage: 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/psimage - from package: GMT

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

On Debian possible default full paths are:

/usr/lib/gmt/bin/psimage - from package: GMT

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

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