Ideogram Reframe aspect_ratio snaps to 1K; Sume's WxH mapping

On Ideogram's Reframe with Nano Banana 2, aspect_ratio "resolves to the closest dimensions the model supports at the 1K output tier", so the ratio you ask for can be adjusted and the returned width and height are what counts. Sume's Nano Banana path maps a WxH size to the native aspect_ratio and documents exact pixels as a post-step, not a guarantee.

Ideogram facts are from its endpoint reference; Sume facts from Image 1.0 and Image generation, read 2026-10-01.

What does Ideogram's endpoint do?

POST /v2/image/reframe/nano-banana-2 expands an uploaded JPEG, PNG or WEBP (up to 50MB) to a new ratio. It is always asynchronous: the 200 response carries a generation_id, a seed, and the resolved 1K width and height, and you poll GET /v2/generations/{generation_id}. Read the dimensions from that acknowledgement instead of assuming your ratio was honored exactly.

How does Sume treat aspect ratio on Nano Banana?

The docs say that on Nano Banana, WxH maps to the native aspect_ratio (their example: 1080×1350 becomes 4:5), and that exact pixels are a documented post-step via job target_pixels. The route takes aspect_ratio and a resolution tier of 512, 1K, 2K or 4K. Check the listed values for the model you use.

What happens if I send an unsupported parameter?

The Sume docs say a parameter the selected model does not list is rejected with 400 unsupported_parameter rather than silently dropped. So a snapped ratio is a documented mapping, while an unlisted field fails loudly.

How do I get the exact output size I need?

Pick the ratio first, then check the returned dimensions, then resize or upscale if a platform needs exact pixels. Upscale to an exact pixel size covers that step, and the ratio changer guide covers the editing side.