additive iterative image generation

One feature that I think would be nice is to start with an image (either an image that I upload, or an image that is generated from a prompt) and then be able to select the areas that I want to keep in the image. Something like a selection tool where I can select parts of the image either using rectangles or freehand selection like the lasso tool in Photoshop. After I have done the selection I should be able to mark the selection as KEEP or REGENERATE. If I choose REGENERATE it would be nice to have a prompt where I can describe what should be generated only for that particular selection. Also it would be nice to make many selections for the same image and have a prompt for each selection to how the selection should be regenerated. It would also be nice to have an undo/redo functionality and some kind of snaphots so that I can easily revert changes and be able to return to various versions of the image that I liked.

Have you tried the "Use as reference image" feature in the "..." menu? You can then use the prompt bar to make some changes and choose how much of the original image you want to keep.