I will explain step by step how to make a PSP theme.

1. First you need the PSP theme maker software, it’s called custom theme converter. You can download it for free.
2. Then Adobe Photoshop software to edit the image.
3. Open the custom theme converter. In the information tab, type some title, product ID and version for your PSP theme.
4. Make the wallpaper. Open the wallpaper in Adobe Photoshop and resize it to 480×272 pixels and save as (.bmp) format with 24-bit color. Then import in the wallpaper tab.
5. Next, in the category icons, create an icon with an image size format of 64×48 pixels, and then click on the file, save for webthing PNG-8 and 256 color format (it’s important, or your icons will break in PSP Themes Creator).
6. In the first level icon tab, you need to make the icon with 48×48 pixel image size format and then click file, save for webThing PNG-8 and 256-color format.
7. Then in the second level icon tab, just create two icons, the default icon and the settings icon. Create the icons with an image size format of 32×32 pixels, and then click on the file, save for webThing PNG-8 and 256-color format.
8. Next in the other tab. Make a preview icon with 16×16 pixel image size format and then click on the file, save for web, thing PNG-8 and 256-color format. Also make a preview image with 300×170 pixels and save it as (.bmp) format with 24bit color.
9. And finally, click on the file, then export and save as .ptf file format.
10. Your PSP theme is ready to put on your PSP.

Thank you for your time.