Mini Frontpage Thumbnails, error in rendering

Hi!
Thanks for your work, MiniFrontpage extension is very useful and easy to use.

Just a question: I found an error in thumbs. Rendering process adds a dark border to the thumb bottom and right side, while original images have not (see sample).
Original images are always B/W and w500px h500px, image placement into article with "images and links" default joomla article fields.
How to solve this issue?

Thank you!
Franz

MMmm yeah that result is unpredictable and not sure where or how to avoid that. What if you adjust the dimension of the thumbnails a little bit?

Same result for 221px, but problem disappears for 219px and 222px!
Maybe the module doesn't like #220?
Thanx a lot!
Franz

Alright, that's good to hear Franz