If you're resizing a smaller rasterized image, the AI Upscale feature can improve the line quality and create a clearer version of your design that can be printed larger. Simply upload a lower resolution or smaller image and resize as normal. When you type in a resizing much larger than the design, the AI Upscale button will automatically appear, it can also be access manually in the Customize tab.
Now you can begin by clicking on the blue Upscale button. It may take up to 30 seconds to Upscale.
Once upscaled, similar to the Picture Stencil Maker, swipe the blue line across the image to see a before and after. Press the blue Apply button when you're ready to use the design.
Or you could trace over your image in the Designer and then delete the original. The drawn lines will be smooth and can be set to any width.