exif_thumbnail() reads the embedded thumbnail of a TIFF or JPEG image. If the image contains no thumbnail FALSE will be returned.
The parameters width, height and imagetype are available since PHP 4.3.0 and return the size of the thumbnail as well as its type. It is possible that exif_thumbnail() cannot create an image but can determine its size. In this case, the return value is FALSE but width and height are set.
If you want to deliver thumbnails through this function, you should send the mimetype information using the header() function. The following example demonstrates this:
Example 1. exif_thumbnail() example
Starting from version PHP 4.3.0, the function exif_thumbnail() can return thumbnails in TIFF format.
Note: This function is only available in PHP 4 compiled using --enable-exif. Its functionality and behaviour has changed in PHP 4.2.0
Note: This function does not require the GD image library.