In 2004, the book Twenty-One Elephants, illustrated by Pham and written by Phil Bildner, also won an Oppenheim Toy Portfolio Gold Award.

The book is narrated by a younger girl who compares herself to her older sister, with their sibling affection showing more as the story progresses.

[4][2] The book received positive reviews, with Linda Ludke in the School Library Journal commenting that “with warmth and good humor, the ups and downs of sisterly love are perfectly conveyed.”[2] Pham is the illustrator of the Princess in Black children's book series.

[5][6] In their The Princess in Black book review, Publishers Weekly said Pham “offers little jolts of energy and wit on every page, with full-page and spot illustrations that have the vivaciousness and irreverence of contemporary animation.”[5] Pham co-created the graphic novels Real Friends and Best Friends with author Shannon Hale.

[7] Through her collaborations with Hale, Pham has been shortlisted for four AML Awards, winning one (for Real Friends) and receiving an honorable mention (for the first Princess in Black book)—making her perhaps the only person unassociated with the Latter-day Saint faith so often recognized.