Perhaps it would be easier to avoid separate lossy and lossless JPEG transformation functions and use general JPEG transformation functions that work according to the options.
The options for the saving of transformed JPEG images should be in "General > Read/Write > JPEG > Transformation" and look ...
Instead of the option "After 'Save As', change filename" in "Options > General > Operations", I suggest to add a command "Save a Copy as ..." to the viewer "File" menu.
For symmetry, there should also be functions for "Replace all" and "Skip all". But to avoid too many buttons, there should be a checkbox "[ ] Apply to all".
1) If you select an image in the browser window, then open it in the viewer window, then move to another image in the viewer window, then switch back to the browser window, the last viewed image will be selected. If the option is off, the first viewed image ...
Options > Interface > Interface: [X] Use different position/size for browser & view (Should be: [X] Allow different window position/size for browser & viewer) [X] Remember last window position/size
^ It's strange that such a usual feature is missing in QT. :o Perhaps you could send a feature request to the QT developers ... In the meantime it would perhaps be possible like this: An additional menu entry "Save with options..." will open the save dialog like "Save as...", but after clicking on ...