ThemeMii is a manager for Wii Themes. The .NET Framework 2.0 is required to run this application!

Current features:

Load mym files and edit them
Create new mym files
Create a csm from any mym
Create a mym from a csm
Browse through base app’s for path’s (including TPL preview)
Download base app’s from NUS
Automatically manage source’s and image width and height

Changes:

Made the window resizable
Added some basic instructions “? -> Help”
Added ability to install a theme directly to a nand backup (Tools menu)
Added option to Lz77 compress containers for smaller csm’s (enabled by default!)
Added option to keep the extracted base app (enabled by default!)
Added save prompt when closing application (can be turned off)
Added I4, I8, IA4 and IA8 as TPL formats (not compatible with MyMenu!!!)
Fixed TPL formats (all images were RGB5A3 before, didn’t matter what you selected)
Fixed a bug when downloading base app
Fixed previewing of Lz77 compressed non-tpl images (base app browsing)
csm to mym: Fixed errors with Yaz0 compressed files
csm to mym: Fixed forgotten containers in mym.ini

http://wiibrew.org/wiki/ThemeMii