There are many directories where one can submit their site There are thousands of directories which means it would be very time consuming unless you are willing to pay a high price for a SEO company to get the job done for you. Even then there is no guarantee. For a lot of us money means a tight budget for the business.
Most free submission directories are very slow to review and list a new site unless of course you are willing to pay for it. Sometimes it takes months to get listed.
My theory is if a lot of unknown or new websites and blogs get together and link up to each other with similar topics and interest then this will help in getting more SEO quality page rank and backlinks for everyone. Then one way is just to sign up with all the free directory services you possibly can.
Just beware that submitting to web directories is very time consuming. Generally, the more established directories are not free. There is normally a backlink required or a submission fee to get your photo website listed if it is approved.