How to Use SVG Vector Graphics in any Version of GameMaker + Studio 1.4 & 2

For the sake of completion, let's get the obvious approach out of the way:
As it stands, you can still use the official Adobe Tools (Illustrator and Animate) to create SWF files, however, if this will stay the case is up for debate:

"Although you can’t edit SWF files directly, you can import them into Adobe Animate. It’s worth noting that if imported, you may miss critical data, such as sound. Alternatively, Flash players may enable simple edits if you want to trim an existing file, but these aren’t officially supported."
- Adobe 2025 (https://www.adobe.com/creativecloud/file-types/video/container/swf.html)

It will be the easiest way if you still hold one of the old licenses or have access to the software in other ways.

However, I assume you reading this means you'd rather just use modern SVG tooling and convert your result.
So let me show you how to convert SVGs to the SWF format without all the paid Adobe tools.

First of all, use Inkscape or something else to create your SVG. Set the canvas size to the size you'd want the sprite to be in GameMaker. Make sure nothing is outside of the canvas. When saving the file, make sure to save a copy as a plain / normal SVG, not as an optimized or "Inkscape SVG" this ensures the other tools understand your file.

Next, use reaConverter online to convert your SVG to an SWF file.

Normally I'd advise you NOT to use online converters for data protection reasons, but here it's by far the easiest and most straightforward way. So go ahead. I've tried out dozens of websites, but there's only one that actually works - when it works!

As reaConverter offers more services for free online than in their free tier software, they may discontinue it any day.

If it works for you, skip straight to step 3.

If your employer prohibits the use of online converters or it gets discontinued, you can always settle for their paid non-Adobe option (Currently reaConverter 7 for Windows).

The software comes in editions, you'll need at least the Standard Edition of reaConverter 7 for this to work from my limited experiments. Older versions may also work.

A free trial is available

Once done, continue with step 3.

This method relies on the old free and open-source software SVG2SWF.
https://sourceforge.net/projects/svg2swf/files/svg2swf/0.5/

Outside of being free indefinitely, it offers no benefit over the prior methods.
Sounds simple enough right? You'd be wrong.
This program is very old, but still works with a catch. It's made for 32bit Windows, specifically Windows XP 32bit.

To save yourself the headache of trying out other Windows versions, set up a Windows XP 32bit VM. There are plenty of tutorials for setting up a VM. If you are on Windows, use VMware Workstation for simplicity.
Remember to not connect Windows XP VMs to the internet

When that's done, transfer the tool and SVG file onto it and run the following command with your paths:

svg2swf.exe input.svg output.swf
input.svg = path to your file (has to exist)
output.swf = path to the output file (will be created)

You'll have to install JPEXS on your PC for this to work. https://github.com/jindrapetrik/jpexs-decompiler/releases

Just import your SWF into JPEXS to delete the added background layer(s) and save/recompile the SWF file.

Please note, you will need to use the draw_set_swf_aa_level and draw_enable_swf_aa functions in GameMaker to enable anti-aliasing of your SWFs, otherwise, they will look very jagged.

draw_set_swf_aa_level(1);
draw_enable_swf_aa(true);

For more information consult the official documentation:
https://manual.gamemaker.io/monthly/en/Settings/Texture_Information/Non-Bitmap_Sprites.htm