Pbase do not supply any facilities to backup your Pbase image files.
In the past a number of members have created scripts or programs that could do this. However, when Pbase makes any changes to the format of the HTML code it is highly likely to stop these third-party programs from working. The author's of the programs then no longer have the time or requirement to make the necessary changes to their code, indeed they may have already moved away from Pbase completely.
One of the more recent third-party programs is mentioned in this thread:
https://forum.pbase.com/viewtopic.php?f=6&t=48495 I don't know if it still works (especially after all the changes make to Pbase code during the switch to the new servers) and, as it's written in Perl, I would hate to have to try and debug it!
Richard T