If you're following the style of older pages and posting as more of a hub for you and all your work,
Posting these pages isn't any different than what's outlined here besides the tags being slightly different.
I think this may need more clarification of how the tags are different — it directs folk to the tagging guide but I think it'd be more effective to just say e.g. "instead of [tag a], use [tag b]" say
That being said, art pages have some more flexibility when it comes to uploading images. You have two main options when it comes to adding images to your art page - hosting on site, and hosting off site.
It feels odd to say this without like, immediately covering why someone should do one or the other of the options (which it doesn't even really say at all — it feels like if someone needs instructions on posting to the site, then covering this would be beneficial? or just, indicating they should do one and letting them discover the other if they really want to?)
With whatever method you decide to use, please read this policy page first.
I think saying e.g. 'the technical content policy' would be more effective here cos it'd be clearer why they should read that — though it also feels like this information should be included here if relevant? Like, the only stuff it covers (according to the next sentence) are the "rules on file size, what file types are allowed, and where you can host your image files if you decide to host them elsewhere" and it feels like all of these can be summarised very quickly in an 'image requirements' box.
As to how to actually make and post your page, the very first thing to do is to make a sandbox page and experiment there first.
Something like "We would recommend creating a sandbox page to experiment with first before posting the page" might be better — this makes it feel like a mandatory step but it also reads clunkily to me.
If you are hosting your images offsite on either Imgur or DeviantArt, go to the site you're using, upload your art to said site, and grab the art's source link or image location link. Usually you'll need to right click the image to get this link. Copy it. Go to your sandbox, open the editor, and click on the insert image wizard. Follow the instructions as the box provides them.
Formatting this as a numbered list of steps might be better; same for the 'hosting images on the page itself' section; and probably the steps to actually post the page too.
If it doesn't, you have the wrong link.
I'd probably lean towards mentioning what to look for in the right link here — which is presumably a file extension at the end?
If you're having issues with the file size being too big, try running your files through this site first before uploading them to the site.
I feel like we should recommend this in general but?