Why do checkboxes move when checked in Safari?

I have a series of values with checkboxes pre-checked on this page. The look and work fine in all browsers, except Safari. When I click on any of the checkboxes they 'jump' or 'drop' down and then move back into position.

I did some research, but I didn't find anything about how to keep the boxes from moving.

Here is the code for the checkbox:

<p><input type="checkbox" class="multiple" value="n" name="n" /><img src="/photos/map/icon_nacelle.png" alt="icon_nacelle" width="25" height="25" /> <span class="filterby">Nacelle<span class="counts" id="n-count"></span></span><br />

<input type="checkbox" class="multiple" value="b" name="b" /><img src="/photos/map/icon_blade.png" alt="icon_blade" width="25" height="25" /> <span class="filterby">Blade/rotor<span class="counts" id="b-count"></span></span><br />

<input type="checkbox" class="multiple" value="t" name="t" /><img src="/photos/map/icon_tower.png" alt="icon_tower" width="25" height="25" /> <span class="filterby">Tower<span class="counts" id="t-count"></span></span><br />

<input type="checkbox" class="multiple" value="f" name="f" /><img src="/photos/map/icon_foundation.png" alt="icon_foundation" width="25" height="25" /> <span class="filterby">Foundation<span class="counts" id="f-count"></span></span><br />

<input type="checkbox" class="multiple" value="tr" name="tr" /><img src="/photos/map/icon_transmission.png" alt="icon_transmission" width="25" height="25" /> <span class="filterby">Transmission/Electrical<span class="counts" id="tr-count"></span></span><br />

<input type="checkbox" class="multiple" value="o" name="o" /><img src="/photos/map/icon_offshore.png" alt="icon_offshore" width="25" height="25" /> <span class="filterby">Offshore Services<span class="counts" id="o-count"></span></span><br />

<input type="checkbox" class="multiple" value="p" name="p" /><img src="/photos/map/icon_professional.png" alt="icon_professional" width="25" height="25" /> <span class="filterby">Professional Services<span class="counts" id="p-count"></span></span><br />

<input type="checkbox" class="multiple" value="fi" name="fi" /><img src="/photos/map/icon_field.png" alt="icon_field" width="25" height="25" /> <span class="filterby">Field Services<span class="counts" id="fi-count"></span></span><br />

<input type="checkbox" class="multiple" value="r" name="r" /><img src="/photos/map/icon_research.png" alt="icon_research" width="25" height="25" /> <span class="filterby">Research/workforce dev<span class="counts" id="r-count"></span></span></p> 

Here is the CSS:

input[type="checkbox"] { 
    width: 25px; 
    height: 25px;
    -webkit-transform: scale(1.3,1.3);
    display: inline-block;
    margin-right: 5px; 
    border: 1px solid #0070BB; 
    } 

How do I