I'm trying to play a video on a Sony Ericsson W350i, but it won't show the image - only play the audio. Does anyone know how I can view the video?

I feel your pain regarding the w350i and the problems you are having getting it to play video. I finally got mine sorted today so let me give you some help which I promise you will work. It took me a month of exchanging angry emails with Sony Ericsson to finally find out the file format, container, and resolution and if you don't get this right, you'll just get audio when you try to play your videos. The people at SE tried to fob me off with "The w350i doesn't play videos" but I wasn't having any of it, and eventually they gave me the information I was looking for.

First of all, get a copy of SUPER from Erightsoft & install it. It's free, and is great because it gives you complete control over the many aspects of a video file. Then choose these settings EXACTLY (ones you can vary to your personal taste are maked with a "*"):

Output Container: 3gp (Nokia/NEC/Siemens) that's right, not the Sony Ericsson option!
Output Video Codec: H.263
Output Audio Codec: AAC

Check the Direct Decode box.

Video Size: 176:144
Aspect: 11:9
Frame/sec: 12.5
Bitrate: 192* (play around with this setting to get your favourite trade-off between file-size & picture quality, but beware that bitrates over 320 will give you audio/video sync issues)

Sampling Frequency: 44,100* (you can set this lower if sound quality is less important)
Channels: 2* (select "1" for mono sound and a slightly smaller filesize)
Bitrate: 112* (for a decent sounding audio, you can reduce if you are using the speaker rather than headphones. If you go any higher you may get sync problems)

SUPER actually lets you save your settings, so if you would like me to send/upload a copy of my settings file, just shout & it will import all these settings for you.

Also, while you are playing around with SUPER, a handy option is to encode only the first "x" seconds of a file. So you can do lots of different short encodes at different settings to find out what works best for you. Just select options on the right hand side of the SUPER window and a pop-out box will appear. Here you can tweak the volume (a little boost is usually good) and also auto generate a jpg you can use as a thumbnail.

Don't bother using the SE transfer software, just drag and drop your 3gp files into the Videos folder on your w350i in file transfer mode.

If you would like me to upload a sample file to see my results and make sure they play on your phone first, just shout.