Pictures in web based emails corrupted

[Daveg4]

Since I have been on NTL broadband 128K using a set top box modem,when I send pictures in web based emails like Hotmail or even my own ISP's email from their website, they come out corrupted the other end.
I can send pictures fine in emails through Outlook Express using my ISP account.
I cant send files through MSN either.
It all works fine if i connect through dialup.
The Max MTU is set to 1500
I use Windows ME and Internet Explorer 6.
Any ideas?

[Kip Patterson]

Try reducing the MTU radically, say to 576, and see if that fixes it. If it does, then you will need to explore to find the maximum possible value. If you need an explanation of how, check back once you know if that's the problem.

Kip

[Daveg4]

Tried 500 and 1000mtu but lo luck.
Tried dialup connection again and pictures still go through ok.
Switched back to cable modem, still not sending pictures without corrupting them.