openSUSE studio imagewriter
is a fantastic
GUI utility for writing raw disk images & hybrid ISOs to USB keys
(in plain English: you can make live memory sticks with it)
https://github.com/openSUSE/imagewriter
1. to download the code, you can find the imagewriter repository in the hyperlink above,
2. click on the green 'Code' button -> Download zip.
3. Extract the archive and
4. open a Terminal window
inside the new folder, where you have extracted it.
5. Run the following commands one by one:
sudo apt-get update && sudo apt-get install qt5-default
qmake DEFINES=USEHAL imagewriter.pro
qmake DEFINES=USEUDISKS2 imagewriter.pro
make
sudo make install
Vlad from the elementary OS forum gave me these very clear instructions.