To download a picture tube, click on the little picture, and then
save the zip file to a place you can easily find it. Then un-zip them to the appropriate folder.
All of the files are .zip files. The files inside the zip are either PSP6 .tub files, or .psp files. Save the .tub files to your TUBES folder (or Picture Tubes, for PSP 8). The .psp files won't be usable with your Tube tool, until you export them as Picture Tubes.