Here is a link:
Also if they are for really small thumbnails you could also just force it to be square.
img src="image.jpg" width=125 height=125
It's better to use inline CSS instead. Like this:
img style="width:125px; height:125px" src="image.jpg" alt="image"
instead of this:
img src="image.jpg" width=125 height=125 alt="image"
Stay compliant with strict (x)html and add an alt tag to your images