Can I use ‘Cburnett’ piece-set in project under MIT License?

I want to ask if I can use the ‘Cburnett’ chess piece–set in a chess website that is covered under the MIT License.
URL of the website: https://perfunctoryorator.github.io/chess/
Its source code: https://github.com/PerfunctoryOrator/chess/tree/main

The website is still under development. (You may as well suggest me regarding improving the website.)

See, I am no legal expert. I took a look at ‘COPYING.md’ in Lichess’s GitHub repository, and it states that the chess pieces designed by Colin M.L. Burnett are licensed under GPLv2+. (What does ‘+’ sign indicate, by the way?) I read somewhere that a software with MIT License can’t include GPL-licensed software inside it.

Another thing is, the website uses Google’s Material Icons, which are licensed under the Apache License Version 2.0, and I read somewhere (else) that Apache License and GPLv2 are incompatible with each other.

So, dear Lichess people, if any of you are knowledgeable in this area, please help me. It would be a relief if the developer(s) themselves clarify this to me.
I have no problem changing my project’s licence to GPLv3, but then the issue is that Apache License and GPLv2 (the pieces’) are incompatible. If the piece set were licensed under GPLv3, it wouldn’t be a problem (I guess).

Hello,

You should be fine as long as you do not modify the image, see https://law.stackexchange.com/a/48439 for a more in-depth answer. The + means it can be licensed as any later version of GPL.

But generally using GPL licenses on non-code is funky at best, because it is not really suited for that.

these pieces are "Triple-licensed under GFDL, BSD, & GPL"
https://en.wikipedia.org/wiki/User:Cburnett/GFDL_images/Chess

@Solal35 said in #2:

Hello,

You should be fine as long as you do not modify the image, see law.stackexchange.com/a/48439 for a more in-depth answer. The + means it can be licensed as any later version of GPL.

But generally using GPL licenses on non-code is funky at best, because it is not really suited for that.
aren't SVGs actually code?

@nonEsiste said in #3:

aren't SVGs actually code?

But is that code created by a human. If not then if you consider them to be code they would not b copyrightable. They images created by human just that storage format is code looking.

@Solal35 said in #2:

You should be fine as long as you do not modify the image, see law.stackexchange.com/a/48439 for a more in-depth answer. The + means it can be licensed as any later version of GPL.
Thanks, I will take a look! :)

@nonEsiste said in #3:

these pieces are "Triple-licensed under GFDL, BSD, & GPL"
en.wikipedia.org/wiki/User:Cburnett/GFDL_images/Chess
That’s some very useful information! Thank you :)