Code: dd if=/dev/zero of=<path to the image file> bs=1024 count=<size in KB>

Code: dd if=/dev/zero of=/sdcard/my_image bs=1024 count=102400

I wrote a small app that requires Superuser and allows you to expose custom disk images instead of the real SD card.Source code: https://github.com/thejh/ImageExposerDownload: https://github.com/thejh/ImageExposer/downloadsTo use this, you will have to:- prepare an empty disk image- create a partition table in the image- create a partition and format it as FAT in the image- copy the image to the android device (if you didn't create it there)Then, open the app, "select new image file", choose the image.Alternatively (that's how I did it), you can expose the empty image right after creating it and then do the partitioning stuff from the PC. Creating an empty image is as easy as running this command on Android (using ConnectBot or so):So, for a 100MB image, use something likeI wrote this app in order to be able to boot linux variants over USB from my sdcard - but sadly, it looks like booting from this thing doesn't work for some reason.Still, it should be usable e.g. for transferring files using the phone over USB while playing music or for preventing people from seeing all the stuff on your sdcard just because you want to take some files home or so.What do you think? Is this stuff usable for something?