All of our image upload form Editor looks blurry.
Checked the setting for that upload field under: Section Editors > [Your Table] > [Upload Field]
Try unchecking this option: [_] Resize images larger than: [___] x [___]
That will prevent it from resizing the images on upload and then you'll be able to see if the resizing was causing an issue or if it was something else.
Hope that helps!