These are the instructions for creating galleries. http://en.support.wordpress.com/images/gallery/ Have you been using them?
If so and you cannot see the images will you please clear your browser cache and cookies and view the pages these images are on again? Is your browser version up to date? You can upgrade any browser version here.
If the images are still not visible to you please post the URL pf the Page in question and provide the URLs of the images in question. We will also need to know exactly which browser and version of it you are using.