why some in Facebook when shear link dosn't display selected image

why some in Facebook when shear link dosn't display selected image either i specify selected image to shear

<meta property="og:image:height" content="240">
<meta property="og:image:width" content="440">
<meta property="og:image" content="http://ift.tt/19vlCg3" />

i use "Open Graph Object Debugger" with this link http://ift.tt/1Ekqu5L i see this result there is no Image appear in , but when mouse hover it i see path of Image , and when i click on image i see image in my website ???

can be server side problem or code problem