Update to Image Editor chapter

Lots of comments and questions:

I suggest the addition of an image color correction divider to the tools tab on the right sidebar in the image editor.

Several Adjust Curves features did not seem to work as stated in the manual. The manual says "The original photo preview has a red marker on it. If you place this marker to a zone you want to modify, a corresponding line will be drawn on the curve grid indicating the original value. Create a point on that line and move it up or down to adjust it to your pleasing." I never saw a red marker. Manual says "Clicking the mouse button in the original image preview area produces a vertical dotted bar in the graph area of the curves tool. The bar position corresponds to the pixel value the mouse cursor is over in the image window. Clicking and dragging the mouse button interactively updates the position of the vertical bar." None of this seemed to work.

Hot Pixels: I don't know what "Select an area to see bad pixels in the preview and the filter result using Separate View options of image panel." means. Does this refer to the Split View comparison types?

Restoration: I did not understand "Note that Detail Preservation must be always inferior to Anisotropy." in the Restoration tool. Does this mean set the Detail Preservation value before Anisotropy?

Sharpen: I removed the statement "Technically this describes the effects of using an (ideal) lens that is not correctly focused." from the manual because it is incorrect. An ideal lens that is in focus blurs not as a circular disc, and not as a Gaussian, but by what is called an Airy function. The point spread function for an ideal lens that is a little out of focus is also not a uniform disc, but is something more complex. I know the British paper you cited said the blur PSF is a uniform disc, and it can get close this in some cases, but it is not generally true. I also wanted to eliminate the term "circular convolution", because that term has a very different meaning in mathematics and signal analysis than what is meant here. But I left it in place as the term was used often, and I did not have a better replacement.

Resize: The manual says "If you want to up-size a small image with a better quality, try the Blowup tool." What is the Blowup tool?

Liquid Rescale: I don't know what this means "If you actually want to get this effect, you need to unset the corresponding option in the Advanced Settings tab." I don't know what option is being referred to.

Liquid rescale: The before and after pictures are basically identical, when the after picture should be 30% narrower.