adjectives - What is the difference between "blurry" and "blurred"?

The two quotes below discuss the same topic.

Terry's tortured season took a surreal twist on Tuesday when a blurry image resembling him appeared on cigarette packets in India. ^GUARDIAN

A blurred picture closely resembling the 31-year-old appears above a "smoking kills" slogan. ^CNN

The definition of blurry and blurred is very identical whereupon blurred has an extended definition. From OALD:

blurry:
without a clear outline; not clear

blurred:
1 not clear; without a clear outline or shape
2 difficult to remember clearly
3 difficult to distinguish, so that differences are not clear

I think that blurry is a derivative of the noun blur while blurred stems from the verb blur. But I wonder why there exists two forms. I tried to find other words where derivatives of both noun and verb with seemingly the same meaning exists to compare their meanings but I didn't find any. Those words which came to my mind have in my opinion a distinction. For instance, washed and washy.

Even though the quotes from the articles give the appearance that they are identical, is there any subtle distinction between blurry and blurred or are they interchangeable without changing any connotation?

Answer

Blurry can always be replaced by blurred (except in the word blurry-eyed), but not always vice versa. IMO, blurry, for the most part, fits all three meanings of blurred in the OALD excerpt, not just the first.

However, blurred has another use which blurry doesn't duplicate, and the dictionary doesn't bring out (probably because it's hard to do without examples). When blurred follows is, was, etc., (i.e. the picture was blurred), it can take a modifier or modifier phrase (e.g. the picture was blurred by the rain or the picture was badly blurred). Blurry cannot be used nearly as extensively in this way.

To go into nuances, even in the places where blurry and blurred are interchangeable, blurred suggests a previous state of non-blurriness and may suggest a perpetrator, whereas blurry only reports the state of the object and doesn't connote much more. The distinction is, however, only slightly observed in common usage.