Yes, if you publish your photographs under copyright protection in the United States, you are subject to a mandatory deposit of two complete copies of the best edition of your work with the Copyright Office, for the use or disposition of the Library of Congress. 
If you register your copyright, you deposit copies of your work with the Copyright Office as part of the registration process, and that also satisfies the mandatory deposit provision.
If you publish your photographs but do not register your copyright, you may still be subject to the mandatory deposit provision. If the Librarian of Congress decides that the Library of Congress needs a copy or copies of your work, you will receive a demand letter from the Copyright Office. Failure to comply within three months can lead to a fine of $250 plus expenses, or $2,500 for a willful or repeated violation.