jpeg - How can I read and write text into a jpg header using PHP? -

i know works photoshop can insert kinds of text serves copyright.

is possible php? how go doing it?

update

i talking meta data in file header, not watermark.

for example, i'n photoshop when open file can click on file-> file info.. , set document title, descriptions, keywords .... way iptc.

i think php exif library want:

the php exif library (pel) lets manipulate exif (exchangeable image file format) data. data digital cameras place in images, such date , time, shutter speed, iso value , on.

using pel, 1 can modify exif data, meaning can both read , written. new exif data can added images. pel written in php , depends on nothing except standard installation of php, version 5. pel hosted on sourceforge.