feMorphology filter

parameters:

operator: erode  dilate
radius: two positives integer for x and y
in: picture to modify

Tool: you can modify operator, x_radius, y_radius and see effect on JPEG or SVG picture
Example: animation focussing on a picture
             animations with radial gradient example 1  example 2

Example of code:

<defs>
<filter id="MyFilter" filterUnits="userSpaceOnUse" x="0" y="0" width="400" height="400">
<feImage xlink:href='#MyImage' result='image1'/>
<feMorphology in='image1' radius='2,2' operator='dilate'/>
</filter>
<image id="MyImage" width='400' height='400' xlink:href='puzzle.jpg'/>
</defs>
<use filter="url(#MyFilter)" x='0' y='0'/>