There may be a much better way so I'll let others chime in.
This logic obviously just creates a dummy file to attach.
But you can get access to your host computer's terminal and do all sorts of activities to retrieve your desired filename.
Then you push to adb.
Here's what I do:
#Push a file from the host to the device
system("mkdir -p /tmp")
system("adb push '/tmp/myfile' '/sdcard/0'")
The file system somewhat depends. You could also replace the above with
/mnt/sdcard/0 and see if that works.
On iOS, I'm not sure if this is even possible as the Camera Roll is read Only.
Alternatively you could link a dropbox or google drive account and somehow access your pictures that way.
Hope this helps and good luck!