Here is my calculation:

28-bit modem would take days to download one pic... I doubt that kind of modem even exists... However...

28800-bit modem = 3.6 kB/s, 216 kB/min, 12960 kB/hour. I will use these numbers, though the real speed is rarely greater than 2.5 kB/s

1 Mbit cable = 128 kB/s, 7680 kB/min, 460 MB/hour. This one I know only from theory...

Now let's assume that the average thumbnail is 10 kB, and average full-size pic is 150 kB:

28800 bps = Theoretically 21 thumbanils per minute, 1296 thumbs per hour, which is more than 86 pages. However, the actual number is 15 thumbs per minute, which is 60 pages in hour. For 6000 thumbnails you would theoretically need 4 hours and 40 minutes. For 6000 full-sized pics you would need more than 69 hours, which is almost 3 days

1 Mbit = 768 thumbs per minute (51 pages), for 6000 thumbs one would need less than 8 minutes. For 6000 full-sized pics you would need 2 hours to download. If the average full-sized pic is 300k, you would need 4 hours. In theory, of course.

I hope this helped. Correct me if I made an error somewhere in calculations...