On every photo page you'll find a share icon. Place your mouse over it to get a list of places you can share the photo on.
You can also share links to your newly posted photos to twitter, autmatically. For that you need to toggle Share on Twitter or Share on Facebook either on the upload page or on your account settings page.
Keep in mind, you'll have to authorize tookapic to post to Twitter on your behalf. We will only post links to your recently posted photo once you publish it on tookapic. To authorize tookapic - click the Facebook/Twitter button on the profile page.