Dear Andre,

 

http://cutesoft.net/ASP.NET+Image+Gallery/Classic-Layout.aspx , this online demo display thumbnails in single page, once you click one image, it will display the full size image.

If you want to download image, you can right click the full size image, and then click "Save as". Every image has one url,  you can  update code and implement the image download feature.

 

Thank you for asking

Eric@cutesoft.net