Metadata

Picture files may contain not only the graphic data, but also some additional (textual) data called metadata. Such metadata are placed to files by almost any digital camera, for instance, and contain as a rule date, time, taking conditions (digicam orientation, flash usage, F-number) etc.

These data may be viewed and even edited by some programs afterwards, and in general the represent quite reliable and valuable source of information, which is stored inside the picture file.

NB: The serious and not always obvious problem is that images can be open by any program disregarding whether contain they metadata or not, and also whether support these programs metadata or not - the file format allows this. The point is that you may easily lose these metadata if you open a file by some not-so-smart program just to, let's say, rotate the image for 90°. When you save the file, the metadata are gone, because the file gets overwritten. So use only smart programs!

Starting with version 1.1.1a, PhoA also gets quite cute thus now it supports reading the metadata of EXIF 2.1 specification - the format of metadata for JPEG files. Metadata read can be viewed, and also can be used for autofilling the picture properties (provided the corresponding options set).

Moreover, to contribute to programs become cute and educated I've decided to open sources for EXIF reading routines at PhoA website.