FluxKontextImageScale - ComfyUI Built-in Node Documentation

Complete documentation for the FluxKontextImageScale node in ComfyUI. Learn its inputs, outputs, parameters and usage.

This node scales the input image to an optimal size used during Flux Kontext model training using the Lanczos algorithm, based on the input image’s aspect ratio. This node is particularly useful when inputting large-sized images, as oversized inputs may lead to degraded model output quality or issues such as multiple subjects appearing in the output.

Inputs

Parameter Name	Data Type	Input Type	Default Value	Value Range	Description
image	IMAGE	Required	-	-	Input image to be resized

Outputs

Output Name	Data Type	Description
image	IMAGE	Resized image

Preset Size List

The following is a list of standard sizes used during model training. The node will select the size closest to the input image’s aspect ratio:

Width	Height	Aspect Ratio
672	1568	0.429
688	1504	0.457
720	1456	0.494
752	1392	0.540
800	1328	0.603
832	1248	0.667
880	1184	0.743
944	1104	0.855
1024	1024	1.000
1104	944	1.170
1184	880	1.345
1248	832	1.500
1328	800	1.660
1392	752	1.851
1456	720	2.022
1504	688	2.186
1568	672	2.333