I have a meditation book for children, it does not have pictures however. It is written for parents to read to their children 'simple visulisations for parents to help children to awaken creativity, sleep peacefully, develop concentration and quiet fears'.

The name is 'Moonbean - A book of meditations for children' by 'Maureen Garth'.

I have had it for a few years and got it from a little new age shop so I am not sure if and where it is available but I thought I would tell you about it anyway.