On an e-hentai gallery page, click "Load more" next to the page numbers and enter how many pages' worth of additional thumbnails you want to load onto the current page.
< Feedback on E-Hentai Load More Thumbnails
The number you entered should be remembered, so if you enter "10" once then you should only have to press enter each time after that. If you want to ALWAYS load 10 extra pages of thumbnails, check out the START_PAGES setting near the top of the script, but be aware that this is probably bad manners. That's why it's not enabled by default.
I made a small change
by changing line 58 to: var desired_pages = 10; You can load what seems to be the maximum number of pages allowed without risking a ban (assuming you're using the minimum number of thumbnails per page in user settings) and without being prompted to input a number every time. I think this is how the script should work by default, personally.