I’ve imaged Ubuntu 15, CentOS 7, and Fedora 21-23 many times.
Ubuntu defaults to extfs while in Fedora 21-23 you can select Ext4 as the filesystem to use.
This is important because FOG only supports ext type file system resizing in Linux. (and only ntfs resizing in windows).
I’m not sure what puppy uses… but it should work as non-resizable at the very least.
Sebastian is on the right path, though. Follow his instructions.