First, we had to store the data in the usual FITS format so that scientists can take full advantage of the pictures. Our goal in publishing this catalog is to provide scientific-quality data for astronomers who may find these galaxy images useful for research or teaching purposes. It was designed to make data transport easy from one machine to another.
FITS files consist of header keys and binary data.
Header keys specify the pixel-resolution of the image, the data type, some information about the actual observation, including the date, time, telescope, camera, observer, filter used, integration time, and coordinates of the object. For more details see the section 3 of this User Guide or the AJ paper published about this catalog. We also think that the galaxy images in this catalog can be interesting for a wider audience. Some people who want to use the data may not have access to image analyzer programs with FITS capabilities. The two file formats generally supported are GIF and JPEG, one of the two formats being better for one or another application.