Change the size of an image, reallocating the color buffer as necessary.
If the image is a sub image (located within a parent), the subimage view on the parent image is updated to the new width and height. The color buffer remains the parent's buffer.
If the image is a parent, a new buffer is allocated. If the previous buffer was specified by the user in RemakeImage, that buffer is not freed, but a new buffer is still created.
If the image is a parent image, the child images are not updated to the newly allocated buffer. Resize works really well for subimages though.