I don't know if this applies to you, but the effect you describe may be something like the following:
When viewing an original photo and a downsized version on a high resultion screen it is not unusual that the downsized version will look somewhat worse. This is an effect due to losing detailed information in the image, but it is only visible, if the image is presented larger than the target size of the downsized version.
You can verify this easily by using a size like 800x530 for an image and then you compare it on your viewer presenting the image to use screen estate equivalent to more pixels than the picture size. You will see that your viewer will render the image differently than the original, because the viewer will try to adapt your picture to the available screen estate, thus making it appear fuzzy. The downsized picture won't look fuzzy once viewer in smaller size.