Thought I'd throw this out there as I see so much on Adobe PS and Lightroom. Photoshop has its place and does some things extraordinarily well. However, I tend to use Corel more than Adobe...
As for Lightroom, try this one from Faststone. Image Viewer. It's free, has all kinds of adjustment options, handles RAW and more. View thumbs on screen, menu options on bottom, left and right screen as you roll mouse on the edges.
Try Photo Resizer for bulk image changes, also free. Two other programs are shareware but these two are FREE.