Praise be to Allah.
Ultrasound images are images of which the features are not clearly defined, and the one who looks at them can hardly make anything out, because this refers to an image that is formed from dark and bright spots, the details of which are known to specialists, doctors and others.
Based on that, the image that is produced by ultrasound is not regarded as coming under the heading of ‘awraat that it is haraam to uncover and must be concealed. But the matter of dignity and decency is broader than the issue of halaal and haraam. Based on that, the woman should conceal these images from strangers (non-mahrams), out of a sense of modesty and dignity, because it is not dignified for her to show them to such people, except in the case of necessity or need, such as a doctor who is treating her, for example.
And Allah knows best.