Hi, thanks so much for the kind review!
I wanted to take the opportunity to announce this "fix". Simple File Lister "inspects" each file to see if it is an image (to add the thumbnail). In this "inspection" it was using the GD Library (Graphical tools) in PHP. GD Library is quite heavy on performance so large files will process very slowly or even crash the server. :o
Per DynaFast's request I added a setting to not use GD Library if a file is over a certain size. The setting is called "GD library size limit".
If you set the GD limit any image bigger than that size will NOT get a thumb-nail but the "paperclip" icon instead.