Should not take more then 15 minutes for someone with experience .
more details :
i have a plugin for wordpress that does a similar gallery but without the movement on mouseover / hover and I need to add that to the plugin .
you need to know how to work with wordpress, install wordpress on your local machine, and a plugin that I give you, .
you need to know how to edit the plugin files (that is self explanatory, but as I see I need to say this for some people...).
the plugin and more details in the attached files !
More details in private . Contact me .