AI studio guide — get the best source image

Midjourney

Use --ar 2:3 or --ar 3:4 for poster ratios. Always export the Upscale (Subtle) version — it preserves the most detail without over-smoothing.

DALL·E 3

Choose the 1024 × 1792 portrait preset. Download the raw PNG, not the WebP screenshot.

Flux

Flux Pro produces excellent poster sources. Render at 1024 × 1536 minimum, leave the default sampler.

Stable Diffusion / SDXL

Use the SDXL refiner pass, then export PNG. Don't apply a community upscaler before sending — let Poster Upscale AI handle it for print calibration.

What to avoid

• JPG screenshots taken from social media
• Phone photos of a screen displaying the AI render
• Heavily compressed downloads from chat clients