如何使用C＃以低分辨率形式提供高分辨率图像

Trying to use 300dpi tif images for display on the web. At the moment, when the user uploads an image, I am dynamically creating a thumbnail. If a page is created referencing the high-res image with a width of 500x500px, can I use the same functionality to convert to a gif/jpg on the fly. What is the impending resolution of the jpg that would be created?Trying to use 300dpi tif images for display on