Some more image sharing sites are there which are more beneficial than you are talking about. Considering following sites would be better:
flickr
fotolog
imageshack
photobucket
panoramio
pixabay
imgur
tinypic
Black hat is an unethical way of practicing SEO techniques. It includes activities like keyword stuffing, cloaking, hidden text, doorway pages, etc. If you do black hat SEO than you might get penalized by google.
Post some original and meaningful content with attractive images on your page on the regular basis in order to get more attention. Keep yourself active on the page.
Cloaking is the process in which there are two versions of same page of which one is serving to search engine bots and another is serving to human. It is a black hat technique which is not legal and can cause penalty by Google
Anchor texts are the hyperlinks in any Content which are mostly applies on your keywords. Code of anchor text is: <a href="http://www.abc.com">Keyword</a>
Crawlers: Crawlers are the programs that crawls your web pages for getting them indexed in web indexes
Index: Index is the huge databases in which your web pages get indexed.
It is a black hat SEO technique which you should not do at all in order to keep your website safe from any Google penality.
In Keyword stuffing you stuff your content by putting keywords again and again.
Update your website on regular basis with quality and unique content..
do article submission, press release submission, social bookmarking, forum posting, blog commenting etc on high PR sites.