Now, now, don't starting yelling things that are not true, just because someone dosn't give you an instant answer. You have asked a question, about doing something "the hard way", and most Tk programmers would not try to do it your way, by manipulating the Tk::Thumbnail module.

I probably would not use Tk::Thumbnail(as you have discovered), and instead make the thumbnails yourself, with Imager or ImageMagick. Then take the thumbnails and display them in an HList or TableMatrix, etc. I would prefer an HList in a left-frame, and the main display in the right frame. You can put as much as you want in an Hlist entry, thumbnails, checkboxes, selection highlighting, etc.

In your second example, you seem to have found a way, (although there is no TK::JPEG), so what do you want to know? If you are looking for an example the way I would do it, look at ztkdb . Here is a screenshot . Now all you need to do is make the -selection option of the HList to be "multiple", and strip off all the database junk which you don't need, and display all selected thumbails in the right frame.