Add mark at images: Resize and apply watermark to images

This class can be use to resize and apply an watermark to an image.

The class can open an image file in the JPEG format, a watermark image in the PNG format, resize the original image to a a given size and apply the watermark image in a given position of the resized image.

The original and the resized images are stored in server files in the JPEG or PNG formats.