When surfing the web over Vodafone UMTS in Germany, you may notice that JPEG images are compressed and displayed in low quality. Press Ctrl-F5 (Strg-F5) in your browser to see the original images on the page. There are several ways around this.

Solution 1 (MS Windows)

Use Vodafone’s HighPerformance Client to set the compression level. This will only help you if your UMTS stick is plugged into your Windows PC. If it is plugged into your router (e.g. Vodafone Surf-Sofort) you’ll need another solution.

Solution 2 (MS Windows)

Use René’s UMTS Proxy.

Solution 3 (Firefox, Linux/MS Windows)

Install the Modify Headers plugin. This is the most elegant solution for Firefox users. Restart Firefox and empty its cache. In ‘Tools’ -> ‘Modify Headers’ add the entry:

Name: Cache-Control
Value: no-cache

On the ‘Options’ tab, check ‘Always On’.

Solution 4

This seems to be the best solution if the UMTS stick is plugged into the router. Run the following Perl script on a PC in your LAN and the issue is solved for all PCs connection to the web via the router: http://www.clasohm.com/blog/20070105/bmctl.pl
To run the script on Windows you’ll need to install Strawberry first.