If you are using GSAK on your PC you can use the GSAK database for GDAK. Just open GSAK, goto Tools/Folder finder..., Select Databases and click Show.
Open the GDAK-folder on your Android device in another explorer-window and copy the databases you want to your device (just copy the whole directory). If explorer gives an error, close GSAK and try again.
Detach your device from the PC, start GDAK and select your database by pressing on the button on the top of the screen.
If you really want to have everything offline you van use the Grabbed Images option of GSAK. Putting them on your Android device is a little more difficult. Reason for that is that a typical SD-card "only" supports about 20,000 entries in a directory. Therefore you have to split them into sub-directories for GDAK:
Go to the GrabbedImages directory in your PC. You can find that directory in the same directory where your databases are. Copy the file files.db3 to the GrabbedImages directory under the GDAK directory on your Android device. This step is very important because this file is needed for the translation of image-links to file-names.
The next step is creating sub-directories under the GrabbedImages directory on your Android device. The names of those directories are not important, personally I use numbers (1, 2 etc). Then copy all images from your PC to the sub-directories on you Android device. Do this in batches with a maximum of 20,000 images.
And that is it. To test it, detach your Android device from your PC, put it in flight-mode (ie: disable all network connections) and test it with a few caches. All images should be displayed.
Normally spoiler pictures are included in the cache-data, but not when you imported them with pocket-queries. You will have to import the cache with the API. In GSAK you can do that with Refresh cache data, in GDAK you can use Refresh. If you do this in GSAK, the spoiler pictures will be included in the GrabbedImages (as soon as you let GSAK grab them).
But it is also possible that spoilers are included in checkers. In this case you can save the picture to a location on your hard-drive (you could make a directory Spoilers in your database directory). Now open GSAK and add a note to the geocache. Click on Picture in the note-dialog, browse to your picture and click on Open. Copy the Spoilers directory to your GDAK directory on your Android device, copy the database to the right directory and your spoiler should be available in the Logs-tab of the geocache.