Add File to Slide Show List (M)

When browsing a folder of images and you are satisfied with the alignment and window position, press 'M' to create a 'Slide Show List' for the images being aligned.
The first time that you do this, you will be asked to provide a name for this new file.
For later playback of the aligned images, specify an interval between images in units of 0.1 seconds.
The alignment information for the first image will be written to the 'Slide Show List'.
A message confirming that information was written is (very) briefly displayed in the title-bar.
The next image will then be displayed. Proceed through the whole batch in this way, remembering to save the alignments for each image.
To create a different 'Slide Show List', press 'Ctrl M' (instead of 'M').