Xwilarg/NHentaiDownloader — reverse-engineered prompt

Build me a simple browser extension for Chrome and Firefox that lets me download a doujinshi gallery from NHentai for personal offline reading. When I’m on a gallery page, add an obvious download button and let me choose ZIP, CBZ, or saving the raw image files.

It should download the whole gallery in order, show progress, tell me if something failed, and use clean filenames so the result is easy to organize. Please include a small options area where I can pick my default format and whether to create one archive or keep the images separate.

Keep it lightweight and easy to install locally in both browsers. Don’t add anything that bypasses paywalls, private restrictions, or access controls. Only download pages the user can already view normally. Look up current browser extension docs online if you need to.