Magnific Popup
Light and responsive lightbox script with focus on performance
...Fits horizontally and vertically, only horizontally, or with no gaps, zoom animation, close icon in top-right corner. If you wish to open the popup only after image is fully loaded, you may preload image via JS. Or use scaled down image instead of thumbnail. Zoom effect works only with images, for now. Animations are added with simple CSS transitions, you can make them look however you wish. Entered data is not lost if you open and close the popup or if you go to another page and then press back browser button. You have full control of what is displayed in popup, align it to any side via CSS, enable or disable scroll on right side of window, whatever.