PartialColor

You can create an image in which all colors other than the selected ones are converted to black and white.
Simply load the image you want, select the eyedropper, and then click on the part of the color you want to keep to complete the process.
Try using it to create a photo or illustration that emphasizes a part of the image, such as the red part or the yellow part.

If you want to change the range to be converted to monochrome or manually determine the color, you can set it from the button on the upper right.
You can also convert the area to gray by touching the desired area after selecting the eraser.