What is this?

This page lets you hide small samples of MP3s in GIF files. For example, here's a picture from Doctor Who, taken from the BBC.

But if you drag this picture into an MP3 player like Winamp, you'll hear the last note of the Doctor Who theme. The MP3 is hidden within the GIF file.

How?

The GIF format allows for an "application extension block" - an arbitrary section for applications that isn't checked by the GIF parser. Meanwhile, Winamp and other MP3 players ignore all data in the file that isn't marked as an MP3 block. The result: the picture viewer ignores the music, and the MP3 player ignores the picture.

...er, what?

Never mind.

What programs do these GIF/MP3s work in?

All picture viewers will be able to show the GIF - and most, but not all, MP3 players will be able to play the music. Winamp definitely works. Windows Media Player doesn't.

What limitations are there?

If you're using this web page, the GIF must be under 40K in size, and the MP3 must be under 80K. All full MP3 tracks will be too large for this - you'll need to cut it down and compress it with a sound editing program. Audacity should work. Some small sound effects and clips will be fine.

Technically, you can use any size of GIF/MP3 you want - but to cut down the load on my server, I'm only allowing small files. Using this, you'll get about 30 seconds of music at the lowest reasonable compression (16kbps, 11kHz mono).

But... I want bigger files than that!

Do it manually. The DOS command copy picture.gif /b + music.mp3 /b combined.gif works almost as well (thanks, Magic Hat Detective), although it doesn't get the GIF header information quite right; on Linux systems, cat picture.gif sound.mp3 > picture2.gif sort-of works too.

Let's go!

Okay, here we go:

First, click 'Browse' and find the GIF file on your hard disk. The file must be less than 40k in size.

Second, click 'Browse' and find the MP3 file on your hard disk. The file must be less than 80k in size.

Next, it's time to upload them. When you click the 'Upload' button below, your computer will upload both the files to this server, and they'll be combined. The resulting picture will be saved here for 5 minutes, but after that it'll be deleted - save it to your own computer. If you want to use it on the web, host it on your own server or use a service like Imageshack.