I keep looking for a way to add borders to images using inkscape.

I ended up making a program that finds images and then adds a rect the same size as the image and groups the image and the new rect together.

If anyone thinks this might be useful the link is here: https://sourceforge.net/projects/krcinktools/files/

Comments are welcome. I would like to make an extension to do this from within Inkscape, but don't really know how to do that.

Welcome to InkscapeForum!

Thanks for making this available. Just to let you know that I'm moving your topic to Inkscape Resources forum. This one is more for images in progress

A few people have asked us for instructional material for making extensions, and unfortunately, there is very little. The developers are focused on the main program, and I'm not sure how extensions actually get made. I guess those with a little programming talent can do it, but I think it is only one language (or maybe 2, I'm not sure) that can be used to write extensions. You could check out this page, under the Developer Documentation section, and somewhere in there, I think, is some limited instruction: http://wiki.inkscape.org/wiki/index.php/Inkscape