Some pages have no infobox because it's quite complex to fill. Some pages have an infobox but no images. You can insert images in the template. You have to upload the photos before use this template because when you type the parameter, you cannot upload images directly like the normal image inserting.
Image should be:
1. large (at least 480x320). It's excellent if you capture images from iPad and the game is HD. (2048x1536)
2. Show full fortress. You should not capture the partial side of the pigs' fortress.
3. Neatly. You must capture screen before you launch the first bird. Do not capture screen when the bird reaches the fortress.
After you upload the photos, type like the lesson 1 (not necessary to write difficulty.) and insert the theme infobox template.
Go to image parameter. This parameter used to fill the full code of the pictures such as [[File:6-1.jpg|250px]] If you write in the image parameter, it will show in the rightmost.Template:Theme InfoboxIn now, this template is changed. If you type like the above, it will show like this.Template:Theme Infobox
You only type 6-1.jpg. Image width is locked by template. It'll show like the rightmost template.
Angry Birds Wiki: Level Walkthroughs Part 1: Guide for Walkthrough Pages
Angry Birds Wiki: Level Walkthroughs Part 2: Level Walkthroughs Contribution
Angry Birds Wiki: Level Walkthroughs Part 3: How to insert the picture in the Theme Infobox template?
Angry Birds Wiki: Level Walkthroughs Part 4: How to use the Theme Infobox template?
Angry Birds Wiki: Level Walkthroughs Part 5: About Difficulty