I'm not an expert with either of the software packages discussed here. Once I know what I want to do I ask the Google oracle for help and it always provides. If you have questions, you should ask Google. There are a lot of videos on YouTube, and some books are available. The learning curve is steep. If you are only going to make one toy and don't intend to make batches or modify the patterns, it may not be worth the effort to learn about these tools.
This isn't a tutorial. It is a simple explanation of how I use Gimp and Inkscape in my toymaking.
The first step I take when making something for the first time is to convert the patterns to SVG. I load the bit map patterns into Gimp and clean them up. The bitmaps get copied into Inkscape and converted into the SVG format.
First I get sharp, precise lines when you print the patterns. When you print from bitmaps the edges of the lines are jagged and fuzzy. If you want to enlarge the pattern, it gets worse. With the SVG format, the jagged edges disappear.
I can enlarge them or shrink them to the size I need with no loss of detail.
I can change the color of the pattern. Some people like to use red lines to help distinguish the blade from the line.
I can get rid of the junk that I don't need like shading, colors, grain lines and text that get in the way and sometimes confuse things or make it hard to see the pattern when I am cutting. They also waste toner.
Want to fill the page with patterns? I have made pages of Play Pals and animal cutouts that I print and get whole pages full of patterns. Perhaps 20 on a page.
One of the things I have been experimenting with is fitting the patterns to the size of the wood I have in Inkscape. I paste and arrange the patterns to fit the wood I am using and print — no more struggling with organizing patterns on my wood with glue on them.
Efficient use of what would be waste is much easier. For example, when I am making my dragon puzzles, two large corner areas are just big enough for a small car or animal cut out. In Inkscape, I paste the patters into these corners. When I'm done cutting that piece of wood, I have a puzzle and two small toys.
Do you want thicker lines so you can see them better? Not a problem. The same is true for wanting finer lines. I'm not too good at this yet, but I'm working on it.
An issue I have not confronted yet but plan to in the future is resizing patterns where the parts need to fit each other precisely. A simple example of this would be a puzzle where you want to make the parts from different colors of wood. Intarsia and segmented scroll saw art would be another.
Gimp and Inkscape are primary tools in my Toy Makers toolbox. Maybe they should be in yours.