My site is image heavy so I store all my images (reduced to 800 by 800 pixels) on another domain and use databases and dynamic pages to show them on the site. I used some normal pages where I had set the Image Settings on "When image it clicked it: Opens a pop-up". Which worked, when an reduced size (say 400 by 400 pixel) image was clicked on the live site the full size 800x800 popped up. Brilliant!
But to reduce pages I am moving to a Dynamic Item page where I try to do the same thing. However, pop up keeps the same size as reduces image size, and does NOT pop up to full 800x800 size. Real bummer, any ideas????

Found a work around by adding a link to the image on the Dynamic Item page that links to a new field in de db with the URL of the full size image, which then pops up in a new browser window when clicked in Live . But would prefer a more straightforward solution :)