Hi Alex,
along the lines of oolong32’s post, would this be possible to add during thumbnail generation:
If an image can’t scale to the set width/height (of say 100×75), it automatically extends the thumb to a width of 100 pixels with the actual image centered on a white background. Or better yet a transparent background, and the file format is PNG.
Alternatively, is it possible to set the thumbnail container to a fixed width and center the image? I suppose that would be a little easier to do.
Best,
-Thomas