Empty slideshow in html project file
Q: I open saved gallery, but it's empty. What happens???
A: VisualLightBox project file stored settings of your gallery only (information about template, image resolution, template of thumbnails, etc), it does not include images.
So if you saved you project as .vislb file and decide to edit created gallery, all the images should be in the same folders/directories they were, when you saved .vislb file.
Otherwise, if you replaced or deleted images .vislb project file won't open correctly.
Anyway you can try to correct(check) paths to images in .vislb file.
Just open it in any text editor and find the following code:
Check values used for <url> tags.