Convert OTB to PPM

The OTB (Over The Air Bitmap) file extension, developed by Nokia, is used for transmitting black and white bitmap images between mobile phones, particularly Nokia and Siemens models. These images, with a maximum resolution of 255x255 pixels, are often sent via SMS in either hexadecimal text or binary format. Historically, OTB files were popular in the early days of mobile communication for sending simple graphics, icons, and wallpapers when data transmission speeds were limited.

The Portable Pixmap (PPM) file extension, an image format within the Netpbm family, stores simple, uncompressed images. Introduced in the late 1980s, PPM supports RGB color and grayscale images, making it suitable for basic image processing and conversion tasks. Its plain text encoding simplifies debugging and data manipulation, although its lack of compression results in larger file sizes compared to modern formats. As such, PPM finds limited use in contemporary applications, mainly in educational and experimental settings where ease of implementation and readability are prioritized.