This module provides integration of IIPImage to Drupal + proper image converting.
"IIPImage is an advanced high-performance feature-rich imaging server system for web-based streamed viewing and zooming of ultra high-resolution images. It is designed to be fast and bandwidth-efficient with low processor and memory requirements. The system can comfortably handle gigapixel size images as well as advanced image features such as both 8 and 16 bit depths, CIELAB colorimetric images and scientific imagery such as multispectral images."
You have to embed Fast CGI module within a host server such as Apache, Lighttpd, MyServer or Nginx.
So, eventually in your root there should be a folder called 'fcgi-bin' with 'iipsrv.fcgi' file in there.
You'll find a documentation about installation of FCGI module for your server here: http://iipimage.sourceforge.net/documentation/server/
Maintenance countdown module provides its own maintenance page with countdown timer, time for this timer can be set in the admin interface. Otherwise, if you don't set time, will be shown a normal Drupal maintenance page or from your theme.