This famous photograph by Man Ray of a French music hall artist is a multiple verbal and visual joke. In French, the translation of the word for a 'hobby' is violin d'Ingres - because the painter Ingres' hobby was playing the violin. Hence, if (say) you were a French lawyer by profession whose hobby was gardening, you might say: 'cultiver mon jardin -c'est mon violin d'Ingres'. OK? Clear now?