Masonry image sizing issues

Hey,

So I have used a similar layout to your Minimal Photography demo on a test site. Im using Masonry to pull in Portfolio Items.

The problem I have is with the automatic size of the images used when applying the tags landscape, portrait or landscape and portrait.

If using both tags (landscape and portrait) for a portfolio item it appears that the image used is a 1500×1000 version, giving a nice crisp/sharp non pixellated image.

However if you assign just a portrait or a landscape tag, to give an image that basically has either the same height or the same width as above it uses a 470×705 or 705×470 version. This results in the image being quite pixellated.

How can I fix?

Thanks,
James.