SmillaEnlarger can automatically process a batch of images with the same settings:
If you drop a folder onto the enlarger, the contents are scanned for images of supported type (subfolders are ignored). To those images the current parameters and the resizing method chosen in the Output Dimensions box are applied at once. The new jobs are moved to the queue automatically, you don't have to press 'Enlarge&Save'.
The results are put into a new folder, the name is that of the source with an appended '_e'.
Also, when you drop multiple files, those are likewise pushed into the queue automatically, but in this case no new folder is created for the batch results.
Important: Before dropping more than one file, check if all settings are as you want, especially look under 'Write Result to:' in which folder the results will be saved ( probably you will want to uncheck 'Use Source Folder' and give a new location where your batch results are saved together ).