my friend uses Microsoft WebTV (e-mail address ends with @webtv.net) and I'd like to send him an e-mail with a picture attached to it.

We went through a series of attempts one of which ended up a success, all others a failure. He just can't see my e-mail in his mailbox, when it contains an attachment. E-mails without attachments always go through all right. What seemed to help in the first successful case, was that he added my e-mail address to his address book and my e-mail suddenly showed up. Seemed to have been delivered before but hidden. He kept my address in his address book however, it didn't help with the following trials.

He did look into his junk folder, nothing there.

I made sure the file name contains no spaces. It's a regular jpeg, named something-like-this.jpg

I downsized it to have only about 50k, as I've read somewhere that that's a limit. I actually doubt this piece of information, because I think the successful attempt was larger.

webtv.net contains zero information. I watched their video demo for the e-mail client, so I at least know how the user interface looks like. I've never laid my hands on the real thing.

I'm an advanced user myself (a programmer) but I can't wrap my mind around this.

He on the other hand, is a very technically inexperienced user and because he's half way across the globe, I can't come and look over his shoulder. He doesn't have a computer, afaik there's no way I could see what he sees.

Any ideas on how to debug this?

Thanks for your time, guys.

P.S. I can't tag this "webtv" because such tag doesn't exist yet and my reputation is too low, sorry.