There are many places one can go to view images of the infamous Mellotron keyboard. In addition to Google Images, one can visit the Sound on Sound website.

The Mellotron, performed by Mike Pinder.

Nicky Hopkins played piano and Brian Jones played the mellotron.

john Lennon was good at singing, guitar, piano, harmonica, banjo, mellotron,6 string bass, percussion, recorder

Mainly Guitars (acoustic, electric, 12-string, slide), but also: bass, Mellotron, synthesizer, dobro, drum programming, percussion, keyboards, piano, harpsichord, organ