I use google's picasaweb to embed photos on my blog, since it's really easy (I cut and paste the code from the picasaweb into my blog entry, et voila, a photo shows up in my post).

But I wanted to jazz them up a bit, and discovered the code to add a border. First find within the embedded code the image source part. It will start with < img src="http:// then have a bunch of gobbledygook with the address of your photo, then it will end with .JPG"/>.

Within that grouping, type in style="border:7px solid black" after the last quotation and before the forward slash. You can change the number before the px to make the border thinner or fatter, and just type in the name of whatever html color you'd like. In the photo below, I used darkkhaki. Here is a link to a chart of the html color names.