Well, no matter what widget you use, if you try to load alot (like > 20) images, it is going to take time. How many are you trying to load at startup?

The only thing I can think of, is to base64encode the images(and their thumbnails) and save them in a Storable hash db. Then at startup, all you need to do is import the base64 coded images into a Tk::Photo object using the -data option. That would save you remaking the thumbnails, and would speed up the read operations. People have been trying to experiment with somehow "freezing" and "thawing" the actual Tk::Photo objects, and importing them from the db. That would be the ideal. It would seem possible to do.

For an example of Storable and Tk (not exactly your situation, but shows the principles) see ztkdb