To add a photo to an MP3, you can use many programs, including Media Tagger, Winamp, etc.

Winamp

1. Open Winamp and right-click on the song you want to add an image to.
2. Select the option View File Info (if your Winamp is in English).
3. Go to the Artwork tab. Under Artwork Type, select "Cover" and then click Load Artwork.
4. Choose the image file from your computer.
5. The image will appear in the small preview window; click OK.
6. Click anywhere in Winamp and enable the option Album Art (this is where the image will appear).

Done! When the song plays, the image you added will be displayed.

Note: You can apply this process to multiple songs at once by selecting them in bulk.

Media Tagger

1. Select the folder containing the MP3.
2. Choose the MP3 file.
3. Click on the image icon located in the top toolbar.
4. On the right side, you will see a space with icons at the bottom. Click on the image icon, which will allow you to browse for the image on your computer.
5. Select the image, and a screen will pop up asking how to tag it (e.g., cover front, cover back, etc.). Choose Cover Front.
6. Click the diskette icon in the top toolbar to save the changes, and you’re done.

Note: Just like in Winamp, you can select multiple songs at once to apply the changes in bulk.