Keeping a large stack of photos on a memory card is always a scary thing in case the memory card goes back. People have created a workaround but using more (and usually smaller) cards to mitigate against the risk. I’ve never like this workaround because of several reasons from not being future proof (photos get bigger and therefore require more space) to importing from multiple cards. A possible solution is using what you may already have: an Android device.
Some Android tablets has a “USB Host” controller which allows it to turn from a device plugged into something (usually a computer) to a “host” device i.e the computer itself. This means it can read from the USB port rather than just push data out to whatever it’s connected to. To do this it’s down to having the correct USB chip in the tablet. To do this you’d need to find out if your Android tablet has this or not and it is very well documented.
Unfortunately I only know of the Android method so people on on other platforms like iOS are out of luck.
Once you know it’s compatible you’ll need 3 other items:
1xOTG cable (USB micro to USB female connector)
1xUSB SD card reader.
The OTG cable can be found and purchased online. It’s even in places like Amazon.
Take care buying a SD card reader because the android device can only provide so much power to the reader. I have had it successfully working on a Sandisk MicroMate. This died on me so I got a cheap replacement from Integral.
As for the App it depends on your device. Before Samsung had native support so no app was required. Others like my Nexus devices (works on phone and tablet) I use the Nexus Media Importer app.
With everything in place and connected it should be intuitive to get up and running. The app should detect the USB being connected and ask if you want to use the Nexus Media Import app.
Using the app you should be able to find, select and copy all the files internally. The app even supports CR2 files (Canon’s RAW file format) so you can preview them.
This serves a great backup for the photos on the SD card. It is only limited by the internal memory available. The more complicated way is to copy it to the tablet, discount the SD Card reader and plug in an external drive and move the copied files off the tablet. To me that seems like too much effort.
With backup sorted the next thing to do is find a way of rating the files so that once they are imported into Adobe Lightroom, they will already have them. Beyond that would be to edit the Jpeg / RAW files so that photos can be posted online in situ pending an Internet connection.
There’s a long way to go before it becomes fully functional but the concept works and hopefully this can be improved upon expanding to rating / light editing.