Under Encoding you’ll need to select either U-Law or A-Law (remember which one you choose). When you choose any other format you’ll be converting the data into that format. Whilst you want to achieve data modification this is bad because it’ll convert the header of the image file, thereby breaking the image. U/A-Law just imports the data. The other settings do have significance but I wont go into that here. When you’re ready press Import and you’ll see your image as data!
Press play if you dare, but I’d place money on the fact that it’ll probably sound like either white noise or Aphex Twin glitchy goodness. This is where the fun can begin. For this tutorial select everything from about five seconds into the audio. The reason for this is because, just like editing an image in a text editor, the header is at the beginning of the file. Unless you know the size of the header and exactly where it ends (which you can find out with a bit of research), you can usually guess that it’s about a few seconds into the audio. The best way to find it out is to try it out!
Anyway, highlight that section and then go to Effect > Echo
Leave the default settings as they are and press OK
You’ll see that your audio has changed visually. It still wont sound any better but the magic happens when you export it back to an image file, which is the next step.
Once you’re happy with your modifications go to File > Export. Choose a new location for your image and type in the proposed new file name but don’t press save just yet. You’ll need to change the export settings to match the import settings.
Change the file format to Other Uncompressed Files and then click on the Options button.
Change the settings to match the ones above (or to A-Law if you imported as A-Law). With that now all set you can now press Save! If you entered a file extension when you were choosing a file name you’ll get a warning about the file extension being incorrect, but you can ignore it and press Yes. If you didn’t choose a file extension, when the file is finished exporting, add the appropriate extension to the file. In my case I’d be adding .bmp to the end.
Here’s the finished image:
There’s of course so many different filters available in Audacity, so try each of them out! If you’re feeling really adventurous try importing two or more different images and then exporting them as a single image.