epub image output: I see something bizarre

I'm using snapshot docbook- ns-xsl

I see something strange on my epub3 output with graphics. It doesn't appear to affect the html; it just seems strange.. Why does width have extra space and a semicolon, but height doesn't? Is it because there is potentially another value to be present in width (but not height). 

I'm not using any parameters or XSLT that might touch these things. I'm just curious about what's going on

Output

    <div class="mediaobject"><img style="width: 150; " src="" height="189" alt="Jack Matthews photo"/></div> 

Input: 

    <mediaobject>
        <imageobject>
            <imagedata  contentwidth="150px" contentdepth="189px" fileref="images-epub/small-small.jpg"/>

        </imageobject>
               
        <textobject>
            <phrase> Jack Matthews photo</phrase>
        </textobject>
      
        
    </mediaobject> 

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Robert Nagle
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