The way to provide screenshots is basically the same way to submit run videos - you need to upload the picture to any image hosting site, and then copy the link to the image on that site. I personally use Imgur: https://imgur.com/upload

you can also put an image in discord like send it to some random empty server of yours or dm to your alt if you have one and get the link of that image. i prefer this over imgur since i use discord alot and i always have it always open