I too like Auto levels.......
I find that PDN can benefit from a Browser.....especially for initial review of new pictures and deleting some....but they already exist and work as well as built in's such as on Paint Shop Pro..
I use the freeware FastStone which does have some editing capabilities, a good screen capture, and allows you to launch any picture into PDN or other graphics program, resize files, e-mail,......the main limitation is it will not view .pdn files but will view a .psd or .tif....
I open FastStone, select a picture, launch PDN or Gimp or whatever....at any time you can open FastStone from the toolbar to review or launch or drag and drop another picture....
I especially like the ability to Edit-Enhance Colors (and retain the slider settings) for use on other photos....this works on one screen, fullscreen....You can save as ,jpg or.tif (to minimize losses) and open or drag to PDN.
I use this as my interface for all my graphics work and did delete Picasa......I also use it to Print from which gives me a single point to print from...