1, teach you a trick. If it is a simple picture, use the drawing software that comes with windows and erase the background color with an eraser. This method is stupid, but practical, haha. If it is a complicated picture, then you can draw more pictures, which is a more painful thing.
What you said are all the standard sentences copied by the examiner in response to the previous paper application. Because your application is electronic, there are not so many requirements. As a supplement, just submit the revised drawings as required.