Logos for each library are saved as vector graphics (SVG file) and PNG image for convenience. For many libraries there is some number of alternative versions. Additionally a consistent set of logos can be found in files logos.svg and logos.png (which is also displayed below). Notice that not all versions of logos can be found there.
To edit and modify a vector graphics you'll need vector graphics editor.
Logos in this repository was created using Inkscape, a multiplatform open source vector graphics editor which can be downloaded here. To install it on Linux with apt-get you can execute sudo apt-get install inkscape in terminal. Tutorials can be found in the Net, e.g. here.
To create a new logo edit one of the existing ones (the best would be the one containing elements you'd like to use in your new logo, e.g. some shapes/arrows) and remove unneeded parts.
