I have a question involving HTML codes. I am new at using them, and I just have a question on editing my Tumblr page.
This is the code I was told to put into my custom HTML.

{IfFadedImages}
img{
-webkit-transition: opacity 0.7s linear;
opacity: 0.70;
}
img:hover{
-webkit-transition: opacity 0.4s linear;
opacity: 1;
}
{/:IfFadedImages}

However, when i plug it in, it just comes up as words on the page as opposed to actually fading my images. Could someone tell me what to do to it so it works? Or edit it themselves, thanks!