Hello, good morning

The images into the gallery from detail hotspot view is always out of focus, blurred... I try set my thumbnails in back end but it was not working well.
I do CSS style in detail view galery images, set it to display the gallery with 1086px of width, So I was upload from my pc images with 1280px of width. But after save the hotspot locale and go to detail view see it all image into the gallery is blurred, but when I clip in expand the image. The image is perfect cover all my pc screen. Why only in the expend is perfect? How can I set the image to display perfect into the gallery too with 1086px of width?

I set backend in multimedia this way:

Small thumb = 50 x 50
Medium thumb = 640x480
Large thumb = 1086x600
Original = 2400x1800

I ll be very grateful for your reply!
Thanks