When posting work that is yours, note it with an [OC] for original content.
When posting work that is NOT yours, post the original artist. If artist is unknown, try to do a reverse image search (such as google image search or TinEye.com). If the artist cannot be discovered, please note this with [Unknown Artist]. Posting of other's work without attribution will lead to the post being removed. Repeated offenses will lead to a ban.
Size notation is only important on photos of physical pieces as this can provide some context for how we are supposed to view the piece.
Where possible, it is also great to note what materials were used in the piece. For example: Digital, graphite on paper, oil on canvas, and so on. This is not required but it is a very nice thing to do.
Thanks for post but it looks like you've posted a video that doesn't give the original artist proper credit in the title or a comment. Giving the original artist credit in the title or in a comment is a requirement of this sub so other artists can get the credit and exposure they deserve. Please see the sidebar for more details.
This is the second time I have had to warn you on this issue. The third time, I will delete your content until the rule is followed.