Image Path from URL

hi friends,
i am having two urls ex:
1. http://hrtest/login.aspx
2. http://hronline/login.aspx


In first URL there will be one Image folder contains lots of files, i have to access tat images in second url in code behind.
Bcoz image file will know at run time only..
first i have to take files containing folder, then have to check is file exists or not then only i will align image url like
string ImgUrlPath  = "http://hrtest/Images/" + Session["EmployeeCode"].ToString();
Image.ImageUrl = ImgUrlPath;
like this i have to assign. this image is in Second URL page



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