I used the Nano-banana Pro AI image generator. I uploaded the background image and the character image as reference images. And I created the combined image using the enhanced prompt:
"Create a full‑body, front‑facing cartoon character illustration of a young girl centered on a living room background in a clean flat vector style. Big round head (about one third of body height) with pastel sky‑blue long hair that sweeps in soft waves and a side part, subtle lighter highlights and smooth gradient shading. Large expressive green/teal eyes with big black pupils, white highlight glints, long upper eyelashes and thin eyebrows; small button nose, tiny closed smile, and soft rosy blush on cheeks. Slim elongated limbs and very thin long legs, simple hands with open palms slightly turned outward and arms relaxed at her sides. Outfit: white sleeveless sailor top with a blue v‑collar and thin white stripe, paired with a short pleated navy blue skirt with a white hem stripe; matching blue rounded flats with low heels. Colors: pastel skin tone, soft sky blues, navy accents, peach skin, bright green eyes. Lighting: soft even studio lighting with minimal shadows, gentle gradients for depth and subtle rim highlight on hair for dimension. Art techniques: crisp vector shapes, smooth outlines, minimal linework, flat cel shading with subtle gradients, high contrast between large shapes and clean negative space. Composition: centered full‑body portrait, straight-on camera angle, unobstructed white negative space around character. Output should look like a modern children’s cartoon character design, high resolution suitable for vector export (clean shapes, layered, 300 dpi)."
After it was complete, I selected the "AI Video Generator" option from the dropdown menu in the top right corner of the image. In the AI Video Generator, I used the prompt: "Retain the exact same flat 2D animation style at in the image. The image is of a soft-lit living room at sunset; the camera follows the young girl in a gentle tracking shot as she turns her back to the lens and walks gracefully toward a plush sofa. In one fluid motion, the camera pans around to capture her turning to face the camera before sitting down, framed in warm cinematic lighting with shallow depth of field" (I also used the "improve prompt" option).