- Removed unused download_page() method (dead code since May 2026)
- Verified Google Images requires JavaScript/Selenium for all downloads
- Updated README.rst to clearly state Chrome/Chromium requirement
- Updated code comment to reflect Selenium is mandatory

The old download_page() method hasn't been called since f93de8d when
we made Selenium mandatory. Google Images no longer returns image data
in non-JavaScript HTML responses.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>