If an image is displaying, you can download it yourself. (Some images display only as thumbnails outside the Library of Congress because of rights considerations, but you have access to larger size images on site.)

Alternatively, you can purchase copies of various types through Library of Congress Duplication Services.

If a digital image is displaying: The qualities of the digital image partially depend on whether it was made from the original or an intermediate such as a copy negative or transparency. If the Reproduction Number field above includes a reproduction number that starts with LC-DIG..., then there is a digital image that was made directly from the original and is of sufficient resolution for most publication purposes.
If there is information listed in the Reproduction Number field above: You can use the reproduction number to purchase a copy from Duplication Services. It will be made from the source listed in the parentheses after the number. If only black-and-white ("b&w") sources are listed and you desire a copy showing color or tint (assuming the original has any), you can generally purchase a quality copy of the original in color by citing the Call Number listed above and including the catalog record ("About This Item") with your request.
If there is no information listed in the Reproduction Number field above: You can generally purchase a quality copy through Duplication Services. Cite the Call Number listed above and include the catalog record ("About This Item") with your request.

Price lists, contact information, and order forms are available on the Duplication Services Web site.

Expect Delays in Service of Nitrate Negatives

Reproductions of all types are available, but Duplication Services anticipates an 8-10 week turnaround in completing orders, as all negatives must be reproduced at their off-site, cold storage facility.

Clues that an FSA/OWI/OEM image may be affected are:
Medium field says "1 negative : nitrate" OR
Reproduction Number field begins with: LC-USF33-

If either is the case, you may wish to consult with Prints and Photographs Division reference staff (202-707-6394). In certain instances, duplicate negatives are available for copying.

Photo, Print, Drawing Advertisements for popular malaria cure, Natchez, Mississippi digital file from original neg.