The nature of copyright law means that it is much harder to make a 'fair use' case for a photograph or other artwork that is reproduced in its entirety (fair use are specific infringing uses that are seen as justified under the law). Consider practicing looking for resources that are available under creative commons, like those listed below:
When searching for digital images in an online database, it is important that you use effective search terms. If you are searching for images of a chair, it is helpful to know what kind of chair you are looking for ... do a little research into the period and style you are interested in by consulting books and other reference sources. Also, consult reference sources to learn more about architectural terms and styles.
If you are looking for books with images of American domestic architecture, here are some helpful Library of Congress Subject Headings to try in WorldCat:
Architecture, Domestic--New England