Album thumbnails

lately the thumbnails of the "album" module are displayed with a very low definition. this happens for the ones I'm creating after the last update. instead for those already created previously the thumbnail is with a good definition. if I'm not mistaken, I reported this a few months ago and then you have solved the problem by sending me a correct file. you can see the problem directly from the home page "edilsocialnetwork.it" at the bottom right of the position indicated as in the attached image. thank you