Inscape – Scalable Vector Images

With the SVG (Scalable Vector Graphics) format you can create images that you can easily change in size.

Wikipedia:
Scalable Vector Graphics (SVG) is a family of specifications of an XML-based file format for describing two-dimensional vector graphics, both static and dynamic (i.e. interactive or animated).
The SVG specification is an open standard that has been under development by the World Wide Web Consortium (W3C) since 1999.

You can create SVG images with the open source program Inkscape.
You can download Inkscape for free.

Open Inkscape

1. Select ‘Draw Bezier’
2. Draw for example an arrow

You can change the color of the arrow;

Save the file with the extension .SVG
The image is now a scalable vector image.
If you open the image with for example GIMP, you can change the size to your own needs without loosing quality.
If you need a smaller or a bigger size image then you created in the first place then you can set here the new settings;