'Permission denied' issues

This may happen while migrating or restoring the shop from backup.

As the first move, set 777 rights to this folders and all their contents:

• image
• storage (the location of this folder should be checked at config.php - DIR_STORAGE)
• catalog/controller/extension

You will not be able to set this rights by FTP or SFTP. Use the file manager in your hoster's control panel for that.