OTA bitmap (Nokia Over the Air Bitmap) is a raster image format intended for use with SMS text messages.
In simplest form, files have a 4-byte header. The first byte is
0x00, the second is the width, the third is the height, and the fourth is
0x01. This defines an uncompressed bi-level image, with a maximum pixel dimension of 255.
If the first byte is not zero, the file begins with one or more bytes containing flags that extend the format. The only extension that appears to be fully defined is one that allows pixel dimensions up to 65535. Incompletely-defined extensions imply that the format could support grayscale and paletted images, compression, and simple animation.
- ImageMagick (format named OTB)