If you use cards to show a child the words in a nursery rhyme, you will be teaching words that are appealing.
Hearing rhymes increases a child's awareness of the sounds that make words similar.
The pictures on the nursery rhyme cards I design go on the back. Children need to associate the look of a word and its sound. Pictures distract from this process. Getting the meaning is no problem once a child learns the sound for a word. The nursery rhyme cards I design are printed on heavy card stock and laminated.