.snIcons {
    filter: opacity(.4);
    -webkit-filter: opacity(.4);
    -o-filter: opacity(.4);
    -moz-filter: opacity(.4);
    -ms-filter: opacity(.4);
    transition: 0.3s filter linear;
    -webkit-transition: 0.3s -webkit-filter linear;
    -moz-transition: 0.3s -moz-filter linear;
    -ms-transition: 0.3s -ms-filter linear;
    -o-transition: 0.3s -o-filter linear;
}

.snIcons:hover {
    filter: opacity(1);
    -webkit-filter: opacity(1);
    -o-filter: opacity(1);
    -moz-filter: opacity(1);
    -ms-filter: opacity(1);
    transition: 0.3s filter linear;
    -webkit-transition: 0.3s -webkit-filter linear;
    -moz-transition: 0.3s -moz-filter linear;
    -ms-transition: 0.3s -ms-filter linear;
    -o-transition: 0.3s -o-filter linear;
}

<div class="sidebar-footer">

              <a href="https://twitter.com/PixcelDev"><img class="snIcons" src="Images/twitter.png"/></a>
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              <a href="https://uk.linkedin.com/in/pixcelstudios"><img class="snIcons" src="Images/linkedin.png"/></a>
              <a href="https://www.reddit.com/user/Pixcel_Studios/"><img class="snIcons" src="Images/reddit.png"/></a>
              <br>
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              <a href="https://github.com/Pixceldev"><img class="snIcons" src="Images/github.png"/></a>
              <a href="http://pixceldev.deviantart.com/"><img class="snIcons" src="Images/deviantart.png"/></a>
              <h3>Copyright Joeb Rogers

</div>

$("#collapse").click(function() {
    $(".sidebar-nav").toggleClass("hidden");
    $(".sidebar-footer").toggleClass("hidden");
    $("#sidebar-wrapper").toggleClass("collapsed");
    $(".sidebar-head").toggleClass("collapsed");
});