1. "
I've mistakenly deleted some photo files during my current session of Puppy."
(a) Are the photo's held on the Linux filesystem inside the pupsave file, or somewhere else?
(b) Did you immediately attempt to use the same file-browser to UNDO the delete before attempting any other actions with the browser?
2. "
is there any way I can just revert to my previous puppysave file?"
There is, provided you have made a backup copy of the pupsave prior to deleting the photo's.
3. "
I'm not sure how often it autosaves itself"
That depends on whether the pupsave is held on an internal HDD, or else a USB connected storage device [Flash Drive?]
e.g.
(a) If on an internal HDD...
The session changes are auto-saved right after each change is made [oh dear!
]
(b) If on a USB connected Flash Drive...
The default save interval is 30-minutes [Ouch!], but...
(c) You may have changed that to zero [0], which means it is NEVER autosaved [you can do it manually].
If you've reconfigured so as to never auto-save, you could also prevent the save that normally takes place at shut-down...
[i.e. power-off improperly, and enter the command
puppy pfix=fsck at the 5-sec pause at the beginning of the subsequent reboot (so as to scan and fix the filesystems of the pupsave and the host partition)]
...And once booted back in, your photo's should be back [the delete not saved].
(d) For future Puppy sessions...
It's possible to make a configuration change to a file...
So that...
[For pupsave files that (are or) APPEAR->(seem to the Puppy) to be held on a USB storage device]...
...At shut-down/reboot you are asked whether you want "to save or not to save".
This avoids the need to power-off improperly in order to "not-save" the session changes during shut-down/reboot.