Follow-up thread:

The reason it was so difficult to find the original post in this case was due to how bad Facebook is with external archivers and search engines.

https://twitter.com/lorgair/status/1647456869638868992

The original Instagram post still exists, but the profile is private. I have screenshots of the post & archives of the pictures; it was a set of 5 images posted on August 19, 2019. The post title reads: "À girl and her pupps ! #gaypride #gay #fiertemontreal #fiertemtl"

I didn't dig too much on the origin of the Folsom Street/Photoshop lie, but this post from Michael Paulausski seems to be a major part of it, spinning it as part of a 4chan operation 'Pridefall':

https://twitter.com/mike10010100/status/1397049036197310464

Michael's thread has a surprise appearance from Cody Johnston, where he accurately attributes the image to Montreal Pride 2019. They argue.

https://twitter.com/drmistercody/status/1397073526289403904

The post above Cody's was deleted, but thankfully some beautiful soul archived it:

https://web.archive.org/web/20210525061427/https://twitter.com/drmistercody/status/1397073526289403904

Apparently Vaush read Michael's thread and amplified this post. I'll have to spend some time to find that stream, but it might be where the whole lie started.

Here's some of the pushback from people who claimed this image was Photoshopped (most after the videos/photos were shown to them):

I've been hesitant to put out FB/Insta links and archives because the profile IDs are embedded in the photo URLs.

Seems clear doing that would be exactly the kind of attention this group is looking for.