Many of these services you don't need to change ... For Google plusone, just edit the line:
<g:plusone href="https://www.photo.gallery/demo/x2/"></g:plusone>
You can either just empty it, and Google will get the link automatically from the page where it is embedded, or add your own link -
Ref for the code is here, but I don't think you need it -
http://www.google.com/webmasters/+1/button/
Similar with Twitter, it uses the page its on, but you may want to change the twitter account:
<a href="http://twitter.com/imagevue" target="_blank" title="Imagevue on Twitter"><img class="largeicon" src="http://cache.addthiscdn.com/icons/v1/thumbs/32x32/twitter.png"/></a>
<div class="container">
<a href="http://twitter.com/share" class="twitter-share-button" data-count="horizontal">Tweet</a>
<a href="http://twitter.com/imagevue" class="twitter-follow-button" data-button="grey" data-text-color="#FFFFFF" data-link-color="#00AEFF">Follow @imagevue</a>
</div>
Basically just change where it says "imagevue" ...
Twitter ref.
http://twitter.com/about/resources/tweetbutton