We all know imagecache is a great module to grab images of any size that are in your site's files/ directory, but sometimes it's hard to get every image to be the right size without black borders on the sides or top. The trick is to know the proper "order of operations".
Here's a fast recipe for square thumbnails that will work with landscape or portrait picture orientations:
Scale - width: 85, height: , upscale: No
Crop - width: 85, height: 85, xoffset: , yoffset: top
Scale And Crop - width: 25, height: 25