Damaged, corrupted and blurry photos on iPhone4

Hello everyone,

I am facing very irritating problem with images clicked by my iPhone camera. When i click, every image comes out fine and with perfect resolution. But after some times, some of them become blurry/ with very low resolution when i see them on iPhone and i am unable to open those images on my computer. Though the properties of images remain the same, but the computer shows this massage - 'Windows can not open this picture because the files appears to be damaged, corrupted or its too large.'

Please help me with this. I've restored and updated the software but the problem remains the same. Kindly look into the matter and provide me a solution.

many Thanks.

- Abhishek