Nokia allowed people to receive 72x14, 1bpp pictures over a series of binary- or hex-encoded SMS messages, and have them show up instead of their carrier name on the home screen. In the 2000s, magazine ads and webpages would distribute them using premium-SMS.
This service, also featuring ringtones, games etc. has been revived, free of charge, by MtF hacker @Manawyrm@chaos.social of the Chaos Computer Club. You can go to Blåmba.de and download all kinds of content into your retro phone.
The service has been discussed in detail at her 38C3 talk: media.ccc.de / YouTube mirror
I also made 10 logos mostly related to Blåhaj, these are already in the Blåmba logo repository.
I welcome feedback and suggestions for future logos!
Those are marvellous and I got the retro bumps :D