What is a Nokia Theme?
Files that contain the .nth file extension are files that have been created by the Nokia Theme Studio software. This software is used to create custom themes for a user's Nokia mobile phone. The NTH file can contain pictures, images, icons and even ring tones that allow you to personalize your mobile phone.
Users can download NTH themes from the Internet. Once the theme has been downloaded to a user's computer, it must be transferred from the computer to the phone so the theme can be installed. Once the theme is transferred from your computer to your phone, it will automatically be added to your phone's theme gallery.
Software that will open or convert NTH files
Media Player Classic - Home Cinema
What is WinRAR?
WinRAR is a shareware file archiver and compressor utility for Windows. It can create archives in RAR or ZIP file formats, and unpack numerous archive file formats.
So it can EXTRACT or COMPRESS .NTH file too.
Using WinRAR to edit .NTH File..
Step 1: Download any nokia theme from various websites available on net.
Step 2: EXTRACT the downloaded Nokia Theme (.NTH File) to any specific folder using WinRAR.
Step 3: By extracting the theme, you will get some Pictures, Images, Icons, Ringtone (sometimes) and an .XML file too.
Step 4: REPLACE those Pictures, Images, Icons, Ringtone by your personal Pictures, Images, Icons, Ringtone, using SAME NAME & SAME EXTENSIONS & SAME DIMENSIONS. Don't edit the .XML file.
Step 5: COMPRESS all of these using WinRAR, with .NTH extension.
See the DEMO ;)