Starting OpenWatch 0.4.0 you can use custom graphical logos that will be displayed on incoming call with associated person.
It works on all SE MBW watches (and Abacus/Fossil watches too).
1a. Download logo(s) from the internet (try searching for Nokia Operator Logo - NOL format)
1b. Draw your own logo
2. Edit the picture - save it as 96x16 monochromatic (1-bit) bitmap. (Required for MBW-200 too, but only area of 80x16 is displayed)
3. Put it on your phone SD card into directory specified in settings (default location is /data/openwatch/). Case sensitive!
4. Name the logo to match the person you want to assign the bitmap with.
4a. +420720123456.bmp (phone number)
4b. Peter.bmp or Peter Jackson.bmp (name that is displayed on incoming call)
You can find hundreds of logos here: http://www.funsms.net/operator_logos.htm
Nokia logos are 72x14, but the BMP size must be 96x16!
To browse NOL filess and save NOL as BMP you can use IrfanView with Plugins.