Images, such as icons, in Apertis are be licensed under CC BY-SA 4.0. When you contribute to any Apertis code repository, you are agreeing to license your work under the same license as the rest of the images in the repository.
Apertis also makes use of other projects which may have other licenses, such as the GPL and LGPL. These are poor licenses for images as they are very difficult or impossible to comply with.
There are two parts to licensing your images:
- include mention of the image licensing in the COPYING (recommended) or README file
- add the license to the image metadata in case it becomes separated from the repository
Add the license to the metadata
You can use exiv2, which is a command-line tool, to write Exif metadata into the file. exiv2 should be available through your Linux distribution or you can download it for Linux or Windows from its website.
For example, if your copyright notice is "© 2016 Alice Artist <firstname.lastname@example.org>" then this command will add it to the Exif.Image.Copyright key:
exiv2 -v -M"set Exif.Image.Copyright Copyright © 2016 Alice Artist <email@example.com>. This work is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA." <path to your image>
Replace the copyright notice with your own and replace <path to your image> with the path to the image which you want to update.
You can now check the copyright notice with:
exiv2 <path to your image>
Which will output something that looks like:
File name : apertis-icon.png File size : 1228 Bytes MIME type : image/png Image size : 36 x 36 Thumbnail : None Copyright : Copyright © 2016 Alice Artist <firstname.lastname@example.org>. This wor k is licensed under the Creative Commons Attribution-ShareAlike 4.0 Internationa l License. To view a copy of this license, visit http://creativecommons.org/lice nses/by-sa/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View , CA 94042, USA. Exif comment :
There may be some other tags present in the output.