Saving Images
Your original raw file will never be altered by RawTherapee.
There are several ways of saving an image from the Image Editor tab:
Save immediately from the Editor tab,
Save via the Queue,
Edit Current Image in External Editor (described in its own article).
Save Immediately
In the Editor tab, if you click on the little hard disk icon

The Save window will by default open the location you saved to the last time you used this window. For your convenience, a shortcut to the folder containing the source image is automatically added to the bookmarks panel on the left side of the Save window. If you want to save the image to the source folder, clicking on this bookmark will save you having to manually click through to navigate to that location.
A shortcut for the OK button is + .
Put to the Head / Tail of the Processing Queue
If you click on the gears icon file:gears.png or in the “Save” window choose “Put to head or tail of the processing queue”, your image will be kept in a queue of files to be processed, so RawTherapee can make the most of your CPU and be responsive while you tweak your photos. Once you’re done tweaking and adding them to the queue, you can have RawTherapee start processing the queue while you go and enjoy some tea. The benefit of putting it to the queue using the “Save” window is that you can individually change the file format, name and destination of each image, whereas putting images to the queue without using the “Save” window will use the settings from the “Queue” tab.
Naming
If your original raw file was called photo_1000.raw, the default
processed file name will be photo_1000.jpg (or .tif or .png).
There is an option in the “Save current image” window: “Automatically
add a suffix if the file already exists”. When checked, you can make
different versions of one raw, which will be saved as photo_1000.jpg,
photo_1000-1.jpg, photo_1000-2.jpg, etc. The same applies when you
send different versions of the same image to the
Queue.