How do you actually download a picture when you click on it? Is there some kind of a javascript code to do just that? Here is how i show the image with pure HTML.
Do you want to open the picture in a new window/tab? Or do you want to download it to the users computer? If you want the user to save the image, then you need to set the content-type of the file they receive:
Remember to check the input so people can't download source files.