This portable version of the classic pc desktop program is perhaps a little overkill for a USB device, but if you feel a compelling need for all the features of the original program, here they are.
To get the portable version of Jarte, scroll down the Jarte web site past the "Normal Install" executable link to the section labeled "Just the Files." Click the zip file link to download.
If you already have Jarte installed on your pc, there is a nifty feature to accomplish the same thing. In the main Jarte window, click on the "Opts" (short for options) button in the upper right corner. The last selection of the resulting menu will be "Install to USB Drive..." When you click that option, Jarte will copy the necessary files to the USB folder of your choice.