Square thumbnails – are they evil?

The first time I saw square thumbnails (ie. thumbnails which are downsized and cropped to square) I thought they were the best thing since sliced bread.

The advantages of square thumbnails are obvious:

• they are really easy to align and never mess up your layout
• the layout will look more uniform and better than with irregular thumbnails
• they do not show everything so they invite the visitor to view the full sized picture

But there is a downside. Square thumbnails alter the composition of the picture. In some cases, when the photographer hasn’t thought much about composition, it can often actually improve the picture. But in other cases, when the composition is deliberate and well thought out, the square thumbnail can destroy it completely.

I use square thumbnails in my photo gallery (have you seen the pictures from my recent cross-country skiing trip?). And I keep wondering whether I should change it to normal thumbnails (normal = scaled down so as to fit into a given rectangle while preserving the aspect ratio).

Do you personally prefer photo galleries with square thumbnails (cropped) or with normal ones?