Rubber Stampede was a rubber stamp company based in Berkeley, California. They issued a large number of Disney-themed stamps including Snow White. These illustration designs date from the 1993 re-release of the motion picture.
Seven Dwarfs, no.A357-E
The Evil Queen, no. A358-D
Hi Ho Hi Ho, no. A359-E
Snow White and Friends, no. A361-D.
Snow White, no A362-D
The Prince, no. A363-D
Rubber Stamp Story Box (42 pieces), no. 951.32
A quick search online reveals quite a few more Snow White pieces by Rubber Stampede than just those we've shown here.