How can I generate a set of thumbnails of equal size without padding?

Question

I am looking for a thumbnail generator which will allow me to batch process hundreds of images and generate thumbnails of a specific size (200x150). IrfranView kind of does this, but it will matte my thumbnails on a background color if they cannot resized to fit the destination size (if I maintain proportions, which I want to). What I want is to size my source large enough to the target size and then auto crop to fit the 200x150 size.

Is there a program that will do this, or is they some painless way I can go this in Irfran view?

Answer 1

You could still do this in a 2-step process in IrfanView.
First resize, setting the short side to 200 pixels (ensuring at least a 200x200 image). Then you run another batch on the result and crop to 200x150.

Answer 2

Imagemagick's convert utility will do what you want.

You need to specify the -thumbnail 200x150^ option, where the ^ indicates to cut/crop.

You can find usage examples here.