Here’s an example. I’ll escape the markdown so you see the raw text:
:quality(80):no_upscale()/2018585659_8_1_230614_022120-w1920-h1280)
The URL contains unescaped parentheses which are illegal in a markdown link because the link itself must be wrapped in parentheses.
This results in my comments showing no pictures and users only seeing this nonsensical text:
:quality(80):no_upscale()/2018585659_8_1_230614_022120-w1920-h1280
If I try to escape the parentheses, I get this:
Oh, hey, it’s the picture!
Whatever admin or bot is editing people’s comments when moving pictures to some other host needs to escape special characters in the URLs.
It’s just an image CDN. It’s used by people running websites to offload the generation of thumbnails (and other smaller sizes) of large images onto a different server (the image CDN’s servers). Images can be resized on-the-fly based on the user’s device and screen size instead of premaking multiple versions of an image in some program like Photoshop.
It has nothing to do with how an image is presented other than to change the native size. It will have literally the same effect as just uploading a larger or smaller version in the first place. Nothing more.