to get the space without finding 4.5GB of images:
find any jpg image (file.jpg)
create a large file (5GB): fsutil file createnew test.rar 5368709120
combine the 2 files: copy /b file.jpg + test.rar bigfile.jpg
format thumbstick
create "DCIM" folder on thumbstick
put bigfile.jpg in thumbstick
remove thumbstick and reinsert
use the autorun dialog to select to upload to dropbox
wait