image showing up as “x”

I am uploading an icon image from stumbleupon

I inserted the code into the single.php adn the text shows up where it is supposed to but the image displays only the image placeholder, no image.

My question is this. The directions I get from other sites when I need to upload icon images say just to upload to your wordpress account. Where exactly should these images be placed? What folder? I tried uploading through wordpress, going to write, post and just using the upload tool. Then they do show up when I look at manage uploads. Should I be linking the image to a page, a file, or no link. Or am I just way off base on everything.

Thanks in advance for any help.