How to reduce bandwidth consumption for Drupal websites
To reduce bandwidth consumption , 1) the simplest way is not to send same file multiple times 2) compress the files when sending from server so that overall size reduces and hence the bandwidth consumption
1. If you are using drupal , you can use the Boost Module http://drupal.org/project/boost.
2. You can save around 50% bandwidth if you can compress your code files HTML, CSS and JS
For HTML, use HTMLCompressor : http://code.google.com/p/htmlcompressor/
For CSS, use CSS Minifier : http://www.cssminifier.com/
3. Use CDN for your media files. CDN is content delivery network, you can google in for details. Put all your image, video and other heavyweight files there
4. Use image presets to save bandwidth big time. Its like sending 10 mb image 3 times when you can send one that is 1MB
On the server side. In order to accomplish that.
use gzip compression for sending to all browers execpt IE.
Use mod expires to only ever send an image once.
5. Remove EXIF headers from your images. This will save you at least 30% on your images
6. Use Cache-Control HTTP header, for images that doesn't change, so that user will not download them every time when visiting the page.
7. Use image resize filter module to resize the images http://drupal.org/project/image_resize_filter. This can be used with ckeditor or tinymce editor. This filter makes it easy to resize images, especially when combined with a WYSIWYG editor such as tinyMCE or CKeditor. Users never have to worry about scaling image sizes again, just insert an image and set it's height and width properties in HTML (this is done automatically by WYSIWYG editors) and the image is resized on output to match the HTML.
8. Check some of the related modules
http://drupal.org/project/advagg - This is the holy grail of CSS & JS aggregation and optimization. If you want your website to load faster, install this module. If you think flushing your CSS/JS directory on certain submit forms is a dumb idea, you should install this module. If you like the idea of using Google's CDN for jquery.js, install this module. It also aggregates JS in the footer. JS minification/CSS compression ... you guessed it install this module. Gzip CSS/JS files, yep it does that too! Using a private file system? Use this module and bring back aggregation for improved performance! Wish you could use the same aggregate on different pages, guess what? Install the bundler submodule and watch in awe of how fast your site loads.
http://drupal.org/project/ie_css_optimizer for Drupal 6 solves the Internet Explorer limitation of loading not more than 31 CSS files per HTML page This problem is fixed in Drupal 7 core. Therefore, there will be no Drupal 7 version of this module.