How to concat a string to xsl:value-of select="...?

You can use the rather sensibly named xpath function called concat here

<a>
   <xsl:attribute name="href">
      <xsl:value-of select="concat('myText:', /*/properties/property[@name='report']/@value)" />
   </xsl:attribute>
</a>  

Of course, it doesn't have to be text here, it can be another xpath expression to select an element or attribute. And you can have any number of arguments in the concat expression.

Do note, you can make use of Attribute Value Templates (represented by the curly braces) here to simplify your expression

<a href="{concat('myText:', /*/properties/property[@name='report']/@value)}"></a>

Three Answers :

Simple :

<img>
    <xsl:attribute name="src">
        <xsl:value-of select="//your/xquery/path"/>
        <xsl:value-of select="'vmLogo.gif'"/>
    </xsl:attribute>
</img>

Using 'concat' :

<img>
    <xsl:attribute name="src">
        <xsl:value-of select="concat(//your/xquery/path,'vmLogo.gif')"/>                    
    </xsl:attribute>
</img>

Attribute shortcut as suggested by @TimC

<img src="{concat(//your/xquery/path,'vmLogo.gif')}" />

Use:

<a href="wantedText{/*/properties/property[@name='report']/@value)}"></a>