Thank you so much!!!! That's the intent; I have so much love for flash dress up games and they used to be SO easy to do, I started making them when I was like 11. It's so sad to see that there's such a barrier to making them now T_T
That's totally fine to ask! Yes, so, Lampy, the creator of MousePSD, has taken down all downloads of their programs and no longer offers support for them unfortunately. That being said, from what I understand of the license, distributing your own forks of the program is completely fine so long as the license file remains in tact, and it looks like someone has reuploaded it packaged to archive.org so it can be downloaded there and run once you unzip the file! :3
Obviously since I am not the uploader I cannot 100% confirm the safety but I DID download it to test it out and it functions just the same as my copy and my computer also did not explode ^_^
For good measure as well, here's an archived version of the original itch.io page, which contains instructions on how the program works + you can read the comments in case you happen to need to troubleshoot one of the couple of issues or have a question that people have asked about there.
Good luck and sorry if my answer is a bit lengthy! I hope this is helpful. I'm not an expert on the program and obviously have no affiliation with the creator but am glad to try and help if you have any issues. If you make anything with it, I'd love to see!!!!!!! The dress up game ecosystem is like, dying.. T_T