Xnview (freeware). You can set the thumbnails to whatever size. I'd suggest a row of 8 along the top. If you click on one on the top (or move along using right-arrow) you see its large preview down the bottom with tabs along the top of the preview to see EXIF, Properties, Histogram etc. Small enough to run from a USB stick. Doesn't need to write to the registry. You can copy an installed version to a USB stick.
You can copy/move selected or tagged files.
Selecting=click on thumbnail or ctrl-click if more than one.
Tagging=spacebar to bring up tag boxes on the thumbnails, spacebar again to toggle tagging on an individual thumbnail.
You then either right-click and select either Copy/Move to Folder or use the Alt-C/Alt-M hotkey. It asks you ( (only asks if you pressed spacebar to enable taggging-mode): Copy/Move: Tagged, Selected, remember choice (don't) ask me again.
You can also perform multi-step batch operations on selected files e.g. resizing, gamma correction etc.
Double-click to open up a a thumbnail for full attention (cropping, filtering, colour adjustment etc). Yo can send a file to an associated program using an F1-F4 hotkey. I send to Pentax Photo Lab & The GIMP.
See
http://www.pentaxforums.com/forums/p...fo-xnview.html to configure it to show EXIF info in diiferent sections of the program.
You can also move the separator between the thumbnail & preview area all the way to the bottom so you could run huge thumbnails (up to 2048x2048) and hide the Preview area completely.
With RAW files, you can configure it to show the embedded JPEG file instead, which speeds up displaying multiple RAW files.