Here at Winaero, and for some of my other projects, I prefer to use a fancy effect for images inserted in blog posts. The lightbox effect, as it is well known, is provided by a number of plugins for WordPress. Once, I changed the theme of my WordPress blog and tried to validate it with the w3c validator, but the HTML markup provided by my previous lightbox plugin was incorrect and not valid. I decided to fix the issue and it was then that I discovered the "Always Valid Lightbox" plugin, which produces valid markup. I was almost completely satisfied until I noticed some problems with it.