The new tendancy is to show larger images. You should go to Configuration > Gallery settings and make sure to set very large numbers (for example) before uploading new images.
Detailed width: 1000
Display width: 600
Tile width: 64
Thumbnail width: 300
This ensures when you upload a new image, it will start with large sizes because the photos always look nice when you downsize, but when the system starts with small images and need to upsize it will look blurry.