What could cause this drop in photo quality? The recent photos I've tried to take with my phone look like the one on left compared to older photos that look like the one on the right.

 


I haven't (knowingly) changed any of the phone settings, and as far as I can see I should be taking the highest quality*/resolution photos possible.

But as you can see all the newer photos are coming out as though they are taken through a rain storm or on a very cloudy day (which isn't the case). Even photos taken indoors with the flash are very poor quality - so poor I deleted them as they were useless for recording the event I was at.

Is this a physical problem with the lens or something in the software I can improve?

* By "quality" I mean lowest compression etc. not a comment on the artistic quality (or otherwise) of the photos.
It looks like this is a physical problem with the camera - either the lens or (more likely) the glass that covers the lens.

On a close inspection of the camera I can see a lot (for the small area) of dark specks on the inside of the outermost lens element.

I don't know what's caused this, but it's this that's causing the reduction in quality of the images.