Fixed size thumbnail

Hi guys, i searched a lot on google about this, but none if those solutions works. Can you recommend some plugin that actually works.

Is there a plugin that scales the image to my custom width, and the rest of the image height that is more than my custom height gets cut off (cropped) ?
I need this because i want my thumbnails to be the same size, without cropping them manually with some software. Plus it would be also nice if i could choose which part to crop.

Thank you a lot !