Some Ecommerce applications such as PrestaShop have an annoying habit of locking image files upon upload. Depending on your FTP servers setup, this can result in the files being inaccessible and preventing you from downloading the files via FTP, or overwriting the files directly. In a typical Plesk environment, the files have deletion enabled which allows you to delete the file and then re-upload them, but this is of no use if you dont have a local copy of the file, such as when the file is renamed by the application.
The only way to unlock these files then is to use a specialist SFTP application such as Directory Opus (our tool of choice), or login to a terminal window via SSH. If you dont have an SSH client, you can get PuTTy from here, or our favourite is the superb UltraEdit which is not only a great text and Hex editor, but has a built-in SSH client.
For Prestashop, log into to your SSH session, cd to your domains image folder eg:
Now list your files with:
you will notice that the permissions are set to -rw------- for each file meaning that they can only be read or modified by the application that created them. We need to give them more friendly permissions and for this we use CHMOD:
chmod 644 *.jpg
Now perfom another list operation and you should see that permissions have changed to -rw-r--r-- allowing you to download or upload the files via FTP. You may want to do this with the category image folder too:
cd ../c chmod 644 *.jpg ls -l
For further information on using CHMOD see http://catcode.com/teachmod/