If Opera users are having problem of image quality, it’s most probably you are running your Opera with Turbo On. By default, Opera keeps it’s « Turbo » ON, which means, images are compressed before it is displayed in the browser. This is done because Opera is trying for a « faster » display in computers having « slow » internet connections.
On the bottom left of the Opera screen, see the green part, and on mouse over, it should display « Opera turbo on ». Click on that to switch it off. Images should now appear properly in your Opera navigator.