File.php extension format on images

Hi,
How can be converted a image into .jpeg extension format?
This image can't be read clearly, but the file format stated as file.php. I got that file when uploaded some pictures from my flash drive. But before that I was able to grab some pictures coming from the net site.
After the actions as I checked on my pictures, the file format was changed. How on earth can I changed into jpeg? I cannot view the content of the file the pictures.
If you have any idea with regards to the error, can you please post it here so that I can learn what is exactly the error is.
Thank You.
