Make it more easy to overwrite the original file
Currently (0.0.4 from flathub), it is only possible to save
the obfuscated to a new location. The file selector opens with an empty filename, located in the home directory, which does not make it easy to overwrite the original file (or even just save the obfuscated file in the same folder as the original image).
The save to file dialog should be prefilled with the original name and a obfuscated
suffix, and opened in the original file directory.