(Courtesy Photo) Second-grade students in Ida Vozzella’s art classes at JP’s Mendell Elementary School, (from left) Azmelanie Perez, Lena Cisler, Carly Chung, Anna Cisler and Martina Reardon, stand next to a display of their art April 1 at Boston City Hall. The students studied the work of Mexican artists Diego Rivera and Frida Kahlo and then created self-portraits in Kahlo’s style.