FluxResolutionPrepare

FluxResolutionPrepare crops and resizes an image to the closest resolution supported by Flux-family models. It can also pre-upscale small sources so you always hit a minimum megapixel target before the final resize.

Inputs

image – The photo to process. Works with a single image tensor.
min_megapixels – Minimum size threshold when pre-upscaling is allowed. If the current image falls below this, the node scales it up before anything else.
enable_pre_upscale – Toggle the pre-upscale step on or off.
crop_width, crop_height – Optional manual crop dimensions. Set to values greater than zero to lock the crop size.
crop_x, crop_y – Offsets for the manual crop. Measured in pixels from the original image before upscale.

Outputs

image – The resized image that fits a Flux-legal resolution.
ratio – Human-readable aspect ratio like 3:4 or 9:21.
target_width, target_height – Final output dimensions.
area_loss_percent – Percentage of the working area trimmed to hit the target ratio.
pre_scale_factor – Amount of pre-upscaling applied (1.0 if no upscale happened).

Where It Fits

Run this node before sending photos into Flux-based diffusion models or any workflow that expects exact width/height pairs. It removes the guesswork when preparing portrait batches for model-friendly input sizes.

Tuning Tips

Keep enable_pre_upscale on when starting with small headshots; it preserves detail before the final resize.
Use manual crop dimensions only when you must enforce a custom region—otherwise let the automatic crop centre the subject.
Watch area_loss_percent; high values mean you’re trimming a lot of the image to meet the target ratio, so consider adjusting the source crop first.

Troubleshooting

Output looks soft – Check if the pre-upscale factor is very high; consider disabling it and doing a manual upscale earlier in the pipeline.
Wrong area cropped – Confirm manual crop values are valid and within image bounds. Clearing them (-1 defaults) restores automatic centering.
Aspect ratio unexpected – Review the candidate list in the node’s widget; the closest match wins. Adjust the list if you need specific pairs.

Screenshot: docs/screenshots/flux_resolution_prepare.png

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