Proble to load images in img.src when my page placed inside subfolder(s)!

Hi
i have a problem to load images into img.src element when my page placed in subFolders!
for example, i've used this syntax to load images :
<img src="../Images/btn5.png" /> This works for these pages :
~/Test1.aspx ~/Folder/Test2.aspx But not working for this page :
~/Folder/SubFolder/Test3.aspx I've searched a lot on the net an tested other techniques which i found from some threads such as '/', '/../'and ... but it does not works for me.
can anybody help me how to accomplish this ?
thanks in advance