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 @[email protected] of the Chaos Computer Club. You can go to Blåmba.de and download all kinds of content into your retro phone.