Display an image

I found a great PHP class that can extract the cover art image from an mp4 file, but it returns the image data in one really long string. I can use file_put_contents() to save the long data sting to a file, such as cover.jpg. Then of course I can display that image on my page, but because I have a huge list of mp4's and am adding to and removing from it all the time, I would rather not extract all the cover art just to save them as more files. My question is this: Using PHP, how can I take raw image data and display it as an image in a page along with other information - without having to save it as a file?

Lauren