Getting empty profile pic when trynig to get it in bigger size android

I am trying to get all user's profile pictures in Facebook using Graph API. Ans I came across a weird problem, when I am asking somthing like this:

http://ift.tt/wljqS4" + d.get(i) + "/picture?width=100&height=100";

It reutrn an empty profile for half of the images, but when I decreas the width and height all is ok again. Someone have an idea what causes it to happen?

I want to get bigger images for better resolution.

And when I type the URL in chrom it says it correct and displaing the images in the given size.