I have noticed that deleting pictures from the Wii Photo Channel Message Board can be tricky for some users. You have to do it from the Main Wii Message Board. Here’s steps on how to do it:

1. Click the envelope in the lower right corner of the Main Menu.

2. Then you find the day on which you posted the particular picture. Click on the envelope to open it.

3. Click the Trash icon in the upper left corner to delete the photo.