Maxima can produce graphics files which may be displayed using the image region provided by a plugin by uni. If the functions Draw2D() and Draw3D are not given a file name to use, a random file name is generated and changed upon each recalculaton. This works quite reliably.
However, if Draw2D/3D is asked to export to a png file which already exists, then this file is not updated. It is also locked in the file manager and can be deleted only when SMath is closed.
There are no such problems with svg images.