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 Batch Queue,
- "Edit Current Image in External Editor" (described in its own article).
In the Editor tab, if you click on the little hard disk icon at the bottom-left of the preview image, or hit the Ctrl+s shortcut, you can "Save immediately". This works as a standard "Save As" dialog. You can select the name and location for the output file (RawTherapee will automatically add the extension based on the chosen format), choose a JPEG, TIFF or PNG format (8-bit and 16-bit for TIFF and PNG), set the compression ratio, choose whether you want the processing profile saved alongside the output image, etc. The last option lets you choose whether you want to "Save immediately" or "Put to the head/tail of the processing queue". A shortcut for OK is Ctrl+Enter. If you choose to "Save immediately", RawTherapee will be busy saving your photo as soon as you click "OK", so it will be less responsive to any adjustments you might try doing while it's busy saving, and it will also take longer to open other images as long as it's busy saving this one. It is generally recommended that you use the queue if you're working on more than one image.
Put to the Head / Tail of the Processing Queue
If you click on the gears icon 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 " Batch Queue" tab.
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 batch queue.