How do you ensure a <td> is exactly 200px tall?

I have a table with an image inside:

<table style="border: 3px solid rgb(0, 0, 0); width: 800px; background-color: rgb(255, 255, 255); margin-left: auto; margin-right: auto; border-collapse: co开发者_开发百科llapse;">
 <tbody>
  <tr>
   <td style="text-align: center; padding: 0px; margin: 0px;"><img style="width: 800px; height: 200px; border: 0px;" alt="Logo" src="logo.png">
   </td>
  </tr>
 </tbody>
</table>

No matter what I do, there is still a little sliver of white at the bottom of the image. A quick check with Chrome's Inspector reveals that the td has a height of 204px!

How can I force the td to be the same height as the image?

As you can see above, I've tried all sorts of things...

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Solution: Add "vertical-align:bottom;" to the image style.
Another solution, not always suitable, is to change the image display type to block, instead of it's original inline display type.
Explanation: The problem occurs due to the automatic behavior of browsers that add a space under the text for characters that are longer than usual. The image is an inline object like text, thus it has a space underneath too.
A great explanation is written in quirksmode.org:

Complication: almost strict mode

In the early days, experiments with strict mode invariably raised the comment that images suddenly got an odd bottom margin that couldn’t be removed. The cause was that in strict mode is an inline element, which means that some space should be reserved for possible descender characters like g, j, or q. Of course an image doesn’t have descender characters, so the space was never used, but it still had to be reserved.

The solution was to explicitly declare images block level elements: img {display: block}.

Nonetheless browser vendors, Mozilla especially, thought this was such a confusing situation that they introduced "almost strict mode". This was defined as strict mode, but with images continuing to be blocks, and not inline elements.

Most common doctypes, including the one I use, trigger almost strict mode. The treatment of images is by far the most important difference between almost strict mode and really strict mode.

Generally you should use a CSS reset document that avoids problems such as this one.

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You'll live a far happier life if you give up the idea that you can create pixel-perfect layouts with HTML.

If you really need pixel precision, you might try tossing the table and using absolute positioning via CSS instead.

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It's 200px tall for me. Can you post an online example?

If it's 4 pixels difference, I'm pretty sure the culprit is what used to be the cellspacing and cellpadding HTML attributes. Can you try setting those to 0 just to see whether it works? The CSS equivalent to that might be border-spacing but I can't try out because it works for me.

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Try the following

table
{
table-layout:fixed;
}