How to fit background-image in td

I am trying to put a background image in a table cell (td) but since the image is larger than the cell I can see only a part of the background image.

The html looks like this:

<tr>
  <td class="active"></td>
  <td class="passive"></td>
</tr>

in the classes I am using this css:

background-image: url('../Images/prospectAct.png');
width: 100%;
height: auto;

The <td> are 8% width and I can make the image fit the cell. Any example that I can test?